Some hemoglobin variants with abnormal oxygen affinity have been reported so far from various regions of the world. They can be classified by their oxygen affinity and 15 variants with low oxygen affinity have been reported. A number of hemoglobin mutants which show an abnormal affinity for oxygen have been reported, but only few cases of hemoglobin Kansas. All cases reported so far are from Japan or in Japanese families. In this paper we describe a Brazilian patient with cyanosis and hemoglobin Kansas diagnosed by an electrophoretical procedure