BackgroundIncarceration has been associated with reduced physical activity. However, physical inactivity is a major cause of morbidity and mortality. The aim of the present study was therefore, to evaluate the incidence and relationship between the measures of physical fitness and the duration of incarceration in of inmates in Kano-Nigeria prisons.MethodA cross-sectional study was done to determine the relationship between the measures of physical fitness and the duration of incarceration of inmates in Kano prisons. Subjects' physical fitness level (cardio-respiratory fitness, body mass index and waist circumference) was assessed using standardized protocols. Simple percentage, Pearson moment correlation test and student's t-test were used to analyze variables of interest.ResultOne hundred and sixteen inmates; 108 (93.1%) males and 8 (6.9%) females participated in the study. The study revealed high (93.1%) prevalence of low cardio-respiratory fitness among inmates and significant correlation between the selected indices of physical fitness (cardio-respiratory fitness, body mass index and waist circumference) and duration of incarceration.ConclusionThe prevalence of low cardio-respiratory fitness was high among inmates and long period of inadequate physical activity may be implicated as causative factor of low physical fitness among inmates in Kano prison. Prison administration and staff should encourage healthy inmate behavior. Provision of adequate facilities to encourage physical activity and sports participation is highly needed.