1932 White Zombie
1934 The Scotland Yard Mystery
1936 Revolt of the Zombies
1936 The Walking Dead
1938 I Accuse
1939 The Man they Could not Hang
1940 The Ghost Breakers
1941 King of the Zombies
1942 Bowery at Night
1943 I walked with a Zombie
1943 The Mad Ghoul
1943 Revenge of the Zombies
1944 Voodoo Man
1945 Zombies on Broadway
1946 The Face of Marble
1946 Get Along Little Zombie
1953 Scared Stiff
1955 The Creature with the Atom Brain
1957 Quatermass II: Enemy from Space
1957 Voodoo Island
1957 Zombies of Mora Tau
1958 The Thing that couldn't die
1959 Invisible Invaders
1959 Plan 9 From Outer Space
1959 Teenage Zombies
1960 The Cape Canaveral Monsters
You can see where this is going. For more info, see this link:
The Ultimate Guide to Zombie Movies