| Men 400m Medley Swimming III World Championship 1978 West Berlin - Tuesday, 22nd August - Gold Medal: Jesse Vassallo, United States | 
| Final |   | time |   | gap | L | ag | 100m | 200m | 300m |  | 1. Jesse Vassallo |   United States | 4:20.05 | WR |   | - | 17 | 59.99s | 2:03.53 | 3:19.15  |  | 2. Serhiy Fesenko |   Soviet Union | 4:22.29 | ER | +2.24s | - | 19 | 58.73s | 2:05.74 | 3:21.49  |  | 3. Andras Hargitay |   Hungary | 4:27.04 |   | +6.99s | - | 22 | 59.83s | 2:08.53 | 3:25.88  |  | 4. Aleksandr Sidorenko |   Soviet Union | 4:27.78 |   | +7.73s | - | 18 | 1:00.40 | 2:08.00 | 3:25.98 |  | 5. Csaba Sos |   Hungary | 4:28.95 |   | +8.90s | - | 21 | 1:00.75 | 2:09.77 | 3:27.83  |  | 6. Scot Matsuda |   United States | 4:29.11 |   | +9.06s | - | _ | 1:00.19 | 2:11.04 | 3:28.00  |  | 7. Simon Gray |   Great Britain | 4:29.95 |   | +9.90s | - | 19 | 59.49s | 2:08.26 | 3:29.40  |  | 8. Bill Sawchuk |   Canada | 4:33.25 |   | +13.20s | - | 19 | 1:00.29 | 2:12.56 | 3:31.82 |   
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| World Record: Jesse Vassalo, United States 4:23.29 (1:00.91, 2:04.72, 3:22.26) |  | Championship Record: Andras Hargitay, Hungary 4:31.11 (1:00.31, 2:09.33, 3:29.32) 1973 |   
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 Heats - Tuesday, 22nd August |  | Best 8 times advanced to Final>.  |   
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| Heat - |   | time |   | gap | L | ag | Rk |  | 1. Serhiy Fesenko |   Soviet Union | 4:27.24 | CR |   | - | 19 |   |  | 2. Andras Hargitay |   Hungary | 4:27.29 |   | +0.05s | - | 22 |   |  | 3. Scot Matsuda |   United States | 4:28.27 |   | +1.03s | - | _ |   |  | 4. Jesse Vassallo |   United States | 4:29.09 |   | +1.85s | - | 17 |   |  | 5. Aleksandr Sidorenko |   Soviet Union | 4:29.59 |   | +2.35s | - | 18 |   |  | 6. Csaba Sos |   Hungary | 4:29.84 |   | +2.60s | - | 21 |   |  | 7. Simon Gray |   Great Britain | 4:30.24 |   | +3.00s | - | 19 |   |  | 8. Bill Sawchuk |   Canada | 4:33.18 |   | +5.94s | - | 19 |   |  | 9. Daniel Machek |   Czechoslovakia | 4:35.54 |   | +8.30s | - | 18 |   |  | 9. Arne Borgstrom |   Norway | 4:35.54 |   | +8.30s | - | 19 |   |  | 11.Guillermo Zavala |   Mexico | 4:36.47 | NR | +9.23s | - | 20 |   |  | 12.Hans-Joachim Geisler |   West Germany | 4:38.55 |   | +11.31s | - | 23 |   |  | 13.Leszek Gorski |   Poland | 4:39.30 | NR | +12.06s | - | 17 |   |  | 14.Rafael Escalas |   Spain | 4:42.46 |   | +15.22s | - | 17 |   |  | 15.Pablo Restrepo |   Colombia | 4:44.34 |   | +17.10s | - | 18 |   |  | 16.Andres Aguilar |   Costa Rica | 4:45.66 | NR | +18.42s | - | 17 |   |  | 17.Claus Bredschneider |   Canada | 4:47.15 |   | +19.91s | - | _ |   |  | 18.Murat Ozuak |   Turkey | 4:50.96 |   | +23.72s | - | _ |   |  | 19.Georgy Dangalakov |   Bulgaria | 4:51.50 |   | +24.26s | - | _ |   |  | 20.Helmuth Levy |   Colombia | 4:54.10 |   | +26.86s | - | 19 |   |  | 21.Tung-Hsiung Hsu |   Taiwan | 4:54.20 |   | +26.96s | - | 23 |   |  | 22.Samir Bouchlaghem |   Tunisia | 4:56.70 | NR | +29.46s | - | _ |   |  | -. Bill Chao |   Taiwan | DSQ |   | - | - | _ |   |   
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