The endogenous stages in Eimeria intestinalis were studied in experimentally infected coccidia- free rabbits by transmission electron microscopy. Four asexual generations were observed. Two types of merozoites were reported. Binucleated merozoites possess all the characteristics of apical complex indicating asexual reproduction by endodyogeny. While the second type, the mononuclear merozoites have one central nucleus. Gamonts were developed mainly from the third generation merozoites where the mature gamonts were recorded together with the fourth generation schizonts. Macro- and microgametogenesis were clearly observed. Development of microgametes and its fine structural characteristics were detected. Mature macrogametes with central large nucleus and the appearance of two types of wall forming body (I, II) were observed. Many reserve food materials including amylopectin granules and lipids droplets
were very characteristic. Control experimentally infected rabbits shed unsporulated oocysts on the day eight p.i.