PROBLEM: The influence of anti-sperm (ASA), anti-phospholipid (APA), and anti-zonal (AZA) antibodies on in vitro fertilization (IVF) results and the need for intracytoplasmic sperm injection (ICSI) were assessed. METHOD OF STUDY: Forty-four couples with infertility of immunologic origin were investigated. ASA in serum and ovulatory mucus were studied by a tray agglutination test (TAT) and indirect mixed anti-globulin reaction test (MAR) test, AZA were studied by passive hemagglutination and commercial enzyme-linked immunosorbent assay (ELISA; BioGen, Germany), and APA were tested by ELISAs in immunoglobulin isotypes IgG and IgM. RESULTS: Because of failed or very low fertilization after standard IVF in the previous cycle, ICSI had to be used in five out of 15 cases with ASA (33.3%), in 16 out of 18 couples with AZA (89.4%), and in only one case if APA were present (9%). Clinical pregnancy rate was 60% in cases with ASA, 38.5% with AZA, and 27.3% per embryo transfer (ET) if APA were detected. CONCLUSIONS: Immunologic infertility can be treated by IVF with very good results. The most important group are women with AZA, in whom IVF–ICSI without any delay is recommended.