Chalcides ocellatus lizards were collected during year 2018 to be investigated for the intestinal parasitic protozoa. Protozoa infection was detected using Immunohistochemistry technique, in addition to assessment of malondialdhyde levels (MDA) and antioxidants markers in intestine and liver of infected and non infected lizards. C. ocellatus lizards were found to be infected with Isospora chalchidis, which reacted positively to immunoglobulin IgG and immunoglobulin IgM. There was an increase in MDA levels in the intestine and liver of infected lizards and a significant increase of GSH levels in liver of infected lizards (P <0.001). For the enzymatic antioxidants, the activity of SOD was evident, there was a significant increase in the intestine and liver of infected lizards (P <0.001). The activity of GST and CAT revealed a significant diminished values in intestine of infected lizards (P <0.001). This study emphasized the role of I. chalchidis in inducing oxidative stress as the increases in MDA and SOD levels and the decrease in CAT, GSH and GST levels in intestine and liver of infected C. ocellatus lizards supporting occurrence of oxidative stress. Moreover, immunohistochemistry technique is an important tool in I. chalchidis detection.