The synthesis of a group of 2-phenylimidazo[1,2-b]pyridazine-3-acetic esters and acids is described. The structures of the new compounds are supported by 1H-NMR spectra. These compounds were tested in vivo for their anti-inflammatory, analgesic and ulcerogenic activity. All new compounds showed remarkable anti-inflammatory action in the carrageenan rat paw oedema (one third of that for indomethacin) but no significant analgesic activity in the acetic acid writhing test together with negligible ulcerogenic action, and were also found to be lacking inhibitory activity on cyclooxygenase in vitro.