Irene Flores, spokeswoman for the local government, said a group of around 120 people from Sub-Saharan Africa stormed the six-metre (20-foot) high fence early Sunday morning.
"Only 30 managed to get through the whole system and get to Melilla," she said, adding they had gone to a local center for migrants and refugees.
Melilla and Ceuta, another Spanish enclave nearly 400 kilometers (250 miles) away, have for some years been a flash point for African migrants trying to enter Spain, with authorities stepping up security by strengthening border barriers, AFP reported.
The border system in Melilla is composed of two six-meter-high fences, with a criss-cross of steel cables in between.
Sunday's incident brings to 10 the number of attempts to storm this fence this year, with some 50 migrants managing to get into Melilla, Flores said.