Prevalence of egg-laying disorders and hematology and blood chemical parameters were analyzed in free-ranging common chameleons (Chamaeleo chamaeleon) from southern Spain. During four reproductive seasons oviposition failures occurred only during dry years. Egg binding appeared to be an important cause of mortality. Oviductal eggs of dystocic females were longer and wider than those of females with normal oviposition. Blood cell counts, white blood cell differentials, hematocrit, and concentration of hemoglobin, total plasma protein, glucose, uric acid, aspartate aminotransferase, and creatinine phosphokinase in blood were determined for eight apparently healthy post-reproductive females and considered as reference values. These chameleons differed from other reptiles in high concentrations of glucose in blood, averaging 362 mg/dl, and in high numbers of heterophils. Females with dystocia differed from reference values in an increase in monocytes and in the high concentrations of aspartate aminotransferase probably associated with tissue trauma.