Emergency contraception was introduced in Nigeria over two decades ago, but few women have used this method even in emergency situations because of the side effects. To find an acceptable levonorgestrel regimen for emergency contraception in our community, the two-dose regimen 0.75-mg levonorgestrel 12 h apart (group A) and the single dose 1.5-mg levonorgestrel (group B) were studied in 1118 volunteers. Mild side effects such as nausea, vomiting, lower abdominal pains, menorrhagia, dizziness, headache, and breast tenderness were reported. Significantly more women in the high-dose group reported headache, breast tenderness, and heavy menstrual flow. Eleven pregnancies (1.0%) were reported (7 in group A and 4 in group B). The crude relative risk of pregnancies was similar in the two groups (RR = 0.71, 95% CI = 0.32-1.55; p > 0.05) [corrected]. On the other hand, the estimated effectiveness rate of 86.80% in group A was significantly lower than the 92.99% for group B (p < 0.05). The pregnancy rates increased with delay in starting treatment and if further acts of unprotected sexual intercourse took place after treatment. It was concluded that both regimens were effective and safe.