diff --git a/src/cartridge.rs b/src/cartridge.rs
index 628cded..264392f 100644
--- a/src/cartridge.rs
+++ b/src/cartridge.rs
@@ -38,7 +38,7 @@ impl Cartridge {
       match cartridge_type {
         0x00 => None,
         0x01 => Some(MBC1),
-        _ => fail!("unsupported cartridge type: 0x{:02X}", cartridge_type)
+        _ => panic!("unsupported cartridge type: 0x{:02X}", cartridge_type)
       };
 
     let rom_size = header[0x48];
@@ -48,7 +48,7 @@ impl Cartridge {
         0x52  => 72,
         0x53  => 80,
         0x54  => 96,
-        _ => fail!("unsupported ROM size: 0x{:02X}", rom_size),
+        _ => panic!("unsupported ROM size: 0x{:02X}", rom_size),
       };
     let mut rom_banks = Vec::with_capacity(rom_bank_count);
 
@@ -62,7 +62,7 @@ impl Cartridge {
 
     let ram_size = header[0x49];
     if ram_size != 0x00 {
-      fail!("unsupported RAM size: 0x{:02X}", ram_size);
+      panic!("unsupported RAM size: 0x{:02X}", ram_size);
     }
 
     let cart = Cartridge {
diff --git a/src/cpu.rs b/src/cpu.rs
index d03e04f..663ef2b 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -176,7 +176,7 @@ impl Addr8 {
           _ => ()
         }
       }
-      _  => fail!("invalid addressing mode for 8-bit store")
+      _  => panic!("invalid addressing mode for 8-bit store")
     }
   }
 }
@@ -209,7 +209,7 @@ impl Addr16 {
     match *self {
       Ind16(addr)   => cpu.mem.storew(addr, val),
       Reg16Dir(r)   => r.store(cpu, val),
-      _ => fail!("invalid addressing mode for 16-bit store")
+      _ => panic!("invalid addressing mode for 16-bit store")
     }
   }
 }
@@ -329,7 +329,7 @@ fn decode_addr(code: u8) -> Addr8 {
     0x05 => Reg8Dir(L),
     0x06 => Reg16Ind8(HL),
     0x07 => Reg8Dir(A),
-    _    => fail!("logic error"),
+    _    => panic!("logic error"),
   }
 }
 
@@ -472,7 +472,7 @@ pub fn decode<R, D: Decoder<R>>(d: &mut D) -> R {
                 d.res((extra >> 3) & 0b111, addr),
         0xc0...0xf8 =>
                 d.set((extra >> 3) & 0b111, addr),
-        _ => fail!("logic error")
+        _ => panic!("logic error")
       }
     }
     0xcc => { let imm = fetchw(d); d.call(CondZ, Imm16(imm)) }
@@ -687,7 +687,7 @@ impl<M: mem::Mem> Decoder<u8> for Cpu<M> {
   }
 
   fn stop(&mut self, val: u8) -> u8 {
-    //fail!("instruction not implemented: stop")
+    //panic!("instruction not implemented: stop")
     4
   }
 
@@ -1149,6 +1149,6 @@ impl<M: mem::Mem> Decoder<u8> for Cpu<M> {
 
   // Undefined/illegal
   fn undef(&mut self, opcode: u8) -> u8 {
-    fail!("illegal instruction: {:02X}", opcode)
+    panic!("illegal instruction: {:02X}", opcode)
   }
 }
diff --git a/src/interrupt.rs b/src/interrupt.rs
index f5e1887..5745262 100644
--- a/src/interrupt.rs
+++ b/src/interrupt.rs
@@ -32,7 +32,7 @@ impl mem::Mem for InterruptCtrl {
     match addr {
       0xff0f => self.flag,
       0xffff => self.enable,
-      _ => fail!("invalid interrupt register"),
+      _ => panic!("invalid interrupt register"),
     }
   }
 
@@ -40,7 +40,7 @@ impl mem::Mem for InterruptCtrl {
     match addr {
       0xff0f => self.flag = val,
       0xffff => self.enable = val,
-      _ => fail!("invalid interrupt register"),
+      _ => panic!("invalid interrupt register"),
     }
   }
 }
diff --git a/src/joypad.rs b/src/joypad.rs
index 9915e81..074b7ca 100644
--- a/src/joypad.rs
+++ b/src/joypad.rs
@@ -91,7 +91,7 @@ impl Joypad {
 impl mem::Mem for Joypad {
   fn loadb(&mut self, addr: u16) -> u8 {
     if addr != 0xff00 {
-      fail!("invalid joypad register");
+      panic!("invalid joypad register");
     }
 
     self.p1
@@ -99,7 +99,7 @@ impl mem::Mem for Joypad {
 
   fn storeb(&mut self, addr: u16, val: u8) {
     if addr != 0xff00 {
-      fail!("invalid joypad register");
+      panic!("invalid joypad register");
     }
 
     self.p1 = (val & SELECT_MASK) | (self.p1 & !SELECT_MASK);
diff --git a/src/main.rs b/src/main.rs
index 7d94307..627dd49 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -105,7 +105,7 @@ impl VideoOut {
                                                    window_height,
                                                    sdl2::video::RESIZABLE) {
       Ok(renderer) => renderer,
-      Err(err) => fail!("Failed to create renderer: {}", err)
+      Err(err) => panic!("Failed to create renderer: {}", err)
     };
 
     let texture = match renderer.create_texture(sdl2::pixels::ARGB8888,
@@ -113,7 +113,7 @@ impl VideoOut {
                                                 video::SCREEN_WIDTH as int,
                                                 video::SCREEN_HEIGHT as int) {
       Ok(texture) => texture,
-      Err(err) => fail!("Failed to create texture: {}", err),
+      Err(err) => panic!("Failed to create texture: {}", err),
     };
 
     VideoOut { renderer: box renderer, texture: box texture }
@@ -172,7 +172,7 @@ fn main() {
 
   let mut cart = match cartridge::Cartridge::from_path(&Path::new(path.as_slice())) {
     Ok(cart) => box cart,
-    Err(e)   => fail!("I/O error: {}", e),
+    Err(e)   => panic!("I/O error: {}", e),
   };
 
   if disassemble {
diff --git a/src/ram.rs b/src/ram.rs
index 2bb0d4f..ce72ff9 100644
--- a/src/ram.rs
+++ b/src/ram.rs
@@ -18,7 +18,7 @@ impl WorkRam {
       0xc000...0xdfff => addr - 0xc000, // WRAM
       0xe000...0xfdff => addr - 0xe000, // WRAM echo
       0xff80...0xfffe => addr - 0xff80 + 0x2000, // HRAM
-      _ => fail!("invalid WRAM address: 0x{:04X}", addr),
+      _ => panic!("invalid WRAM address: 0x{:04X}", addr),
     }
   }
 }
diff --git a/src/serial.rs b/src/serial.rs
index 4f5fa67..8f26915 100644
--- a/src/serial.rs
+++ b/src/serial.rs
@@ -24,7 +24,7 @@ impl<'a> mem::Mem for SerialIO<'a> {
     match addr {
       0xff01 => self.data,
       0xff02 => self.control,
-      _ => fail!("invalid serial I/O register"),
+      _ => panic!("invalid serial I/O register"),
     }
   }
 
@@ -48,7 +48,7 @@ impl<'a> mem::Mem for SerialIO<'a> {
           self.control &= !SERIAL_TRANSFER_FLAG;
         }
       }
-      _ => fail!("invalid serial I/O register"),
+      _ => panic!("invalid serial I/O register"),
     }
   }
 }
diff --git a/src/timer.rs b/src/timer.rs
index b192dbc..41f04c6 100644
--- a/src/timer.rs
+++ b/src/timer.rs
@@ -67,7 +67,7 @@ impl mem::Mem for Timer {
       0xff05 => self.tima,                                  // TIMA register
       0xff06 => self.tma,                                   // TMA register
       0xff07 => self.tac,                                   // TAC register
-      _ => fail!("invalid timer register"),
+      _ => panic!("invalid timer register"),
     }
   }
 
@@ -77,7 +77,7 @@ impl mem::Mem for Timer {
       0xff05 => self.tima = val,     // TODO: is this correct?
       0xff06 => self.tma = val,
       0xff07 => { self.tac = val; self.tima_cycles_mod = 0 },
-      _ => fail!("invalid timer register"),
+      _ => panic!("invalid timer register"),
     }
   }
 }
diff --git a/src/video.rs b/src/video.rs
index 0657eea..9e24624 100644
--- a/src/video.rs
+++ b/src/video.rs
@@ -362,7 +362,7 @@ impl mem::Mem for Video {
       0xff49 => self.obp1,
       0xff4a => self.wy,
       0xff4b => self.wx,
-      _ => fail!("invalid video address: ${:04X}", addr),
+      _ => panic!("invalid video address: ${:04X}", addr),
     }
   }
 
@@ -384,7 +384,7 @@ impl mem::Mem for Video {
       0xff49 => self.obp1 = val,
       0xff4a => self.wy = val,
       0xff4b => self.wx = val,
-      _ => fail!("invalid video address: ${:04X}", addr),
+      _ => panic!("invalid video address: ${:04X}", addr),
     }
   }
 }