Introduction. – Gastrointestinal disorders in solid organ recipients may have various origins including cryptosporidiosis and microsporidiosis. The prevalence of these infections is poorly known in solid organ transplant (SOT) patients in industrialized countries. Methods. – We prospectively assessed the infectious causes of diarrhea in SOT patients. Secondary objectives were to gain further insight into the main characteristics of cryptosporidiosis, and to assess risk factors for this infection. All adult kidney and/or pancreas recipients presenting with diarrhea and admitted to our facility between May1, 2014 and June 30, 2015 were enrolled. As tool sample was analyzed using a standardized protocol including bacteriological, virological, and parasitological investigations. Data related to clinical symptoms, immunosuppression, and environmental potential risk factors were collected through a self-administered questionnaire and computerized medical records. Results. – Out of 73 enrolled patients, 36had infectious diarrhea (49.3%). Viruses ranked first(17/36),followed by parasites and fungi (11/17). Cryptosporidiosis was the most common parasitic disease (n=6 patients). We observed four microsporidiosis cases. The estimated prevalence of cryptosporidiosis and microsporidiosis in this cohort was 3.7 and 2.40/00, respectively. No significant risk factor for cryptosporidiosis or microsporidiosis, neither environmental nor immunological, could be evidenced. Conclusion. – Both cryptosporidiosis and microsporidiosis represent a significant cause of diarrhea in kidney transplant recipients.