Caffeine has calciuric and osteoclasteogenesis effects. Objectives: To examine the association of caffeine cumulative dose and duration of therapy and the Osteopenia of prematurity (OP) Study design: A retrospective observational cohort study included premature infants less than 31 weeks and birth weight less than 1500 grams. OP was evaluated using chest X-rays on biweekly basis over 12 weeks hospital stay. Caffeine cumulative dose and duration of therapy, steroid dose and diuretic dose along with other maternal and neonatal risk factors were collected to examine their impact on OP. Results: The cohort included 109 infants. 51% had OP and 8% had spontaneous rib fractures. Using the generalized mixed model, Caffeine dose and duration of caffeine displayed strong association with OP. Steroids and vitamin D had significant correlation with OP while diuretic use did not show statistical significant effect. Conclusion: Caffeine cumulative dose and duration of therapy are associated with OP.