Background: Doripenem is a recent carbapenem not commercially available in Nigeria with broad spectrum antibacterial activity against various clinical infections. Carbapenems have been shown to be the last line of agents against ESBL producing organisms.Objective: To determine the in-vitro activity of Imipenem and Doripenem against ESBL producing Klebsiella spp.Design: A cross-sectional laboratory based study.Setting: The University of Ilorin Teaching Hospital, a major tertiary hospital in Ilorin, the capital of Kwara state in Nigeria.Subjects: All strains of Klebsiella spp isolated from all clinical specimens collected at the hospital laboratory non– repetitively.Result: Doripenem had a superior in-vitro activity compared to imipenem with MIC 50/90 value of 0.0125/0.023 while imipenem was found to be 0.19/0.38 which was statistically different.Conclusion: The result obtained in this study is similar to those from other studies and therefore re-affirms the superior activity of doripenem compared to imipenem and should therefore be introduced as a better alternative to imipenem against ESBL producing organisms