Detection of Pneumocystis jirovecii and its DNA in clinically asymptomatic people is defined as colonization. The aim of this study was to reveal the colonization prevalence of P. jirovecii and affecting factors in an immunocompetent population. The study included 200 cases undergoing forensic autopsy between February 2015 and April 2015. The cause of death was non-medical conditions (group 1) in 111 cases (55.5 %), medical conditions (group 2) in 73 cases (36.5 %) and undetermined (group 3) in 16 cases (group 3). Tissue specimens about 1 g in weight were taken from the right upper pulmonary lobe. After DNA extraction, nested PCR targeting mitochondrial large subunit rRNA was used to detect P. jirovecii. Of 200 cases, 37 (18.5 %) had P. jirovecii DNA. There was not a significant difference in place of living, gender, smoking status and medication use between the cases with P. jirovecii and those without P. jirovecii. A significantly high rate of P. jirovecii colonization was detected in group 2 (χ2=7.674; P=0.022). P. jirovecii-colonized cases also had a chronic disease in 2 of 13 (group 1), 12 of 20 (group 2) and 1 of 4 (group 3) cases (χ2=5.571; P=0.062). A significantly high rate of the cases aged 0-1 year had P. jirovecii (5/11; 45.5 %) (χ2=5.639; P=0.018). The results of the study suggest that infants and patients with chronic diseases like cardiac or pulmonary diseases can be at risk for P. jirovecii colonization.