Because of the fall in population in Europe, the evaluation of causes of male infertility is becoming more and more important. Testicular biopsy is a useful method of examination in the area of assisted reproduction. Testicular biopsies of 85 infertile males were evaluated histologically. According to the sperm count, 31 patients had azoospermia, 22 oligo-astheno-teratozoospermia (OATS), 29 oligozoospermia, and 3 astheno-teratozoospermia. The biopsies were carried out by atraumatic microsurgery. Samples were taken from the upper inner and lower outer quadrant of both sides. Bouin-fixed, paraffin-embedded blocks were cut and HE slides examined. Samples taken from azoospermic patients showed atrophy, maturation arrest, normal histology or Sertoli cell-only syndrome. Oligozoospermic patients presented maturation arrest, hypospermatogenesis or normal histology. In the OATS group maturation arrest hypospermatogenesis and atrophy were found. The spermatogram groups showed significant correlation with the homogeneity of the spermatogenesis. The sperm count alone is not sufficient in assessing spermatogenesis. Four samples give more adequate information than just one, because spermatogenesis is not homogeneous in the testis. After evaluating diagnostic biopsies, tissue for TESE can be taken from the most appropriate location in the testis.