OBJECTIVE: Sperm DNA integrity has been reported to be an effective marker to predict the outcome of ART (IVF and ICSI) treatments. DESIGN: The main objective of this work was to determine the influence of sperm DNA fragmentation on pregnancy and abortion rate in a group of 340 couples attempting ART. MATERIALS AND METHODS: 340 semen from 340 men of couples undergoing ART were analyzed using the sperm chromatin dispersion assay (SCD) (Halotech DNA, Madrid). The samples were divided into two main groups according to the percentage of fragmented DNA (DFI = DNA Fragmentation Index): a group with DFI ≤ 30% (n = 258) and a group with DFI >30% (n= 82). The number of pregnancies, considered with a bHCG level > 10 mIU/ml on the 14th day, and the abortion rate were calculated in the two groups. RESULTS: No significant differences were seen among the two groups with regard to the pregnancy rate: 31% in the ≤30% DFI group and 34% in the >30% DFI group. A difference, but still not statistical significant, was seen in the pregnancy outcome: the abortion rate was 38% in the ≤30% DFI group and 46% in the >30% DFI group. By considering only couples undergoing ICSI we obtained 31% pregnancy in the ≤30% DFI group (n = 169) and 35% in the >30% DFI group (n = 63). The abortion rate was 37% respectively 50% in the two groups. By eliminating the couples with women older than 40 years but considering FIVET and ICSI, pregnancy and abortion rate were respectively 38% and 29% in the ≤30% DFI group (n = 168) and 37% and 41% in the >30% DFI group, (n = 45). Only the difference in the abortion rate is significant among the 2 groups. CONCLUSIONS: These data demonstrate that the sperm DNA fragmentation test is an important tool only to predict the probability of pregnancy failure. Moreover, the increase of the abortions in the group with high DFI if only ICSI treatments are taken into account, is in contradiction with previous results, where ICSI was suggested as the therapy of choice by sperm with a high DFI to overcome the late paternal effect.