The study of the clinical and epidemiological characteristics of infectious process caused by Chlamydia pneumoniae and Chlamydia psittaci in our medium, Cáceres.We are reviewed retrospectively clinical aspects of the patients with infections due to Chlamydia in the las five years. We accepted patients with compatible symptoms and serologic demonstration of recent infection with conventional complement fixation and/or microimmunofluorescence assay, the last used to distinguish Chlamydia pneumoniae.We are studied sixteen patients (9 males and 7 females), sixth median age 46.6 (26-70). Fifteen patients was diagnosed in winter. We found five cases of Chlamydia pneumoniae and three of Chlamydia psittaci. In the other eight cases we didn't distinguish between Chlamydia pneumoniae and Chlamydia psittaci. All patients had fever, accompanied by lung symptoms and pulmonary infiltrates in the 75% of them. The most frequent clinical information was the discord between the pulse and temperature (81%). Splenomegaly was observed in three patients (19%) being the diagnosis of them psitacosis. Nine patients had respiratory insufficiency and eight (50%) disturbance in hepatic enzymes. The clinical presentation in one patients was as unknown origin fever.The infection produced by Chlamydia in the hospitalary medium isn't much diagnosed in our unit. The months of winter favour the infection. We think that splenomegaly is the only different characteristic in these infections, suggesting psitacosis.