The following Corrigendum from the British Journal of Haematology, published online in Wiley Online Library (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2141.2010.08188.x/pdf) on 22 March 2010 and in Volume 149, issue 2, page 307, has been retracted by the Journal Editor-in-Chief, Professor Finbarr Cotter, and Blackwell Publishing Ltd. The retraction has been made because it was subsequently determined that Mr Syed Jamal was never involved in the project that resulted in the original publication listed below. -- Iyamu, E.W., Jamal, S., Ekekezie, C. & Woods, G.M. (2007) In vitro evidence of the inhibitory capacity of chloroquine on arginase activity in sickle erythrocytes. British Journal of Haematology, 139, 337–343.