This study aimed to evaluate testicular function of rabbit exposing to subchronic toxicity of formaldehyde and possible protective role of L-carnitine. A total twenty Newzealand adult male rabbits divided randomly into four equal groups were used. For Three months, the first control group (CG) received saline, second group (FA) received formaldehyde in milk, third group (FA+LC) received the L-carnitine in combination with formaldehyde in milk and the fourth group (LC) received 250 mg∕kg L-Carnitine orally. Animal weight, sexual desire, reaction time, semen analysis and testicular blood flow estimated each 15 days. There were no significant differences in the sexual desire, reaction time between groups. The body weight, ejaculate volume, sperm motility, alive sperm percent and sperm cell count were dramatically decreased (P<0.001), while sperm abnormality percent and pH increased in FA group. On the other hand, the motility, viability percent and sperm cell count increased with marked decrease (P < 0.001) in sperm abnormality percent in L-carnitine group. FA group showed an increase in the intratesticular blood perfusion. Formaldehyde subchronic toxicity has dramatic adverse effects on the rabbit semen and could be overcomed using L-carnitine.