Debutants
Roberto Visentini is the youngest debutant in World Championships in 1978. There are 36 debutants.
| # | Rider | Team | Age |
|---|---|---|---|
| 1 | VISENTINI Roberto | Italy | 21y + 86d |
| 2 | VAN DER VELDE Johan | Netherlands | 21y + 258d |
| 3 | BERNAUDEAU Jean-René | France | 22y + 50d |
| 4 | SHERWEN Paul | Great Britain | 22y + 81d |
| 5 | SVENDSEN Kim-Gunnar | Denmark | 22y + 246d |
| 6 | HAVIK Martin | Netherlands | 22y + 255d |
| 7 | VAN VLIET Leo | Netherlands | 22y + 285d |
| 8 | WEHRLI Josef | Switzerland | 23y + 267d |
| 9 | SCHMUTZ Gottfried | Switzerland | 23y + 305d |
| 10 | GISIGER Daniel | Switzerland | 23y + 322d |
| 11 | BETZ Heinz | Germany | 23y + 332d |
| 12 | BELDA Vicente | Spain | 23y + 349d |
| 13 | JAKST Hans-Peter | Germany | 24y + 35d |
| 14 | SCHEUNEMANN Bert | Netherlands | 24y + 136d |
| 15 | KELLER Fridolin | Switzerland | 24y + 153d |
| 16 | SCHÖNBACHER Gerhard | Austria | 24y + 214d |
| 17 | VILARDEBO Pedro | Spain | 24y + 315d |
| 18 | AMRHEIN Guido | Switzerland | 25y + 19d |
| 19 | BOLLE Thierry | Switzerland | 25y + 98d |
| 20 | HAYTON Dudley | Great Britain | 25y + 126d |
| 21 | LANGERIJS Hans | Netherlands | 25y + 225d |
| 22 | CHAUMAZ Gilbert | France | 25y + 227d |
| 23 | BETZ Werner | Germany | 25y + 228d |
| 24 | VAN DEN HAUTE Ferdi | Belgium | 26y + 63d |
| 25 | HINDELANG Hans | Germany | 26y + 319d |
| 26 | LUALDI Valerio | Italy | 26y + 361d |
| 27 | CHASSANG Jean | France | 27y + 200d |
| 28 | GAVAZZI Pierino | Italy | 27y + 266d |
| 29 | DIDIER Lucien | Luxembourg | 28y + 22d |
| 30 | CARBUTT Paul | Great Britain | 28y + 54d |
| 31 | MCQUAID Pat | Ireland | 28y + 356d |
| 32 | VÖGELE Meinrad | Switzerland | 29y + 70d |
| 33 | CLAUSEN Finn | Denmark | 30y + 189d |
| 34 | FREDBORG Niels | Denmark | 31y + 303d |
| 35 | CREPALDI Ottavio | Italy | 33y + 98d |
| 36 | REIMER Freddy | Denmark | 33y + 359d |