Background: A decade before Kenya's independence in 1963 thousands of 'Mau Mau' fighters were arrested and incarcerated in concentration camps where many underwent torture and inhuman treatment. No studies have been done to establish the presence of post traumatic stress disorder (PTSD) and other psychiatric morbidity among the survivors of those concentration camps. Objectives: To establish the prevalence of PTSD and other psychiatric morbidity and associated factors among the Mau Mau Concentration Camp survivors. Design: A cross-sectional, descriptive study of all consecutive concentration camp survivors included in the study. Setting: Mau Mau War Veterans' Association (MMWVA) headquarters at Mwea House, Nairobi, Kenya Human Rights Commission headquarters in Nairobi, Tumaini House (Venue of MMWVA elections, 2005) and the MMWVA branch office in Kajiado District, Rift Valley Province, Kenya. Subjects: One hundred and eighty one Mau Mau Concentration Camp Survivors who gave consent to participate in the study. Main outcome measures: Lifetime and Current PTSD, IES-R score and other Psychiatric Morbidity as measured using the SCID and the IES-R. Results: A DSM-IV-TR diagnosis of current PTSD was made in 65.7% of the survivors. Current PTSD was associated with higher IES-R scores and older age, lower income, non-Catholic religion, larger household size, older age at incarceration, greater length of incarceration, incarceration in two or more camps, experiencing other traumatic events, family history of mental illness and having other psychiatric illness. Conclusions: Similar to other former Prisoners of War (POWs) elsewhere, these survivors suffer high PTSD prevalence rates and a special veterans' service is recommended to address this problem and its associated factors among these and other veterans in Kenya.