The aim of this study was to evaluate chromatin condensation and sperm head morphometry of semen samples from bulls Bos indicus, as well as their fertility potential. Thawed semen from 40 bulls, considering 3 ejaculates per animal, was evaluated by means of Toluidine Blue staining. Once smears were prepared, images were captured under a light microscope (1000x). A minimum of 100 gray-scale images of spermatozoa per smear were obtained and the mean gray intensity of the heads in each image was determined by using software developed in the SCILAB environment  (Beletti et al., 2003). The fertility potential was determined based on the in vitro production of embryos, adopting 3 groups: Chromatin alteration (3 bulls with the highest percentage of chromatin alteration), normal chromatin (3 bulls without chromatin alteration) and control (laboratory control bull). Results were analyzed according to ANOVA and means were compared according to Tukey's test (P<0.05). Semen analyses revealed that spermatozoa with abnormal chromatin condensation (A) are larger than those showing normal chromatin condensation (N) (A = 2194.8 ± 509.08 pixels; N: 1792.1 ± 324.28 pixels; P​<0.0001). There were no significant differences in cleavage and total number of blastocysts (D7 and D8), evidencing that the proportion of sperms with abnormal chromatin (4 to 16.15%) did not affect the embryonic development. Under normal conditions, DNA damage at a low level is repaired by the oocyte (Matsuda et al., 1989; Genesca et al., 1992), but when severe, it may induce apoptosis, early embryo fragmentation or late morbidity (Hwang et al., 1997; Ji et al., 1997; Sun et al., 1997). We suggest to discard morphologically larger spermatozoa in reproductive biotechnologies in order to prevent failures in the embryonic development or other future complications. Acknowledgements: FAPESP for financial support.