In a screening of glucose-6-phosphate dehydrogenase (G6PD) A variants in the Canary Islands and northwest African populations by electrophoresis and posterior gene sequencing, the common A+ 376G and A- 202A/376G and the rare A- 376G/968C mutations were found. In addition, three new silent C-->T transitions have been detected at nucleotides 759 (exon 7), 1338 (exon 11), and 1573 (exon 13). Canary Island and North African samples share sub-Saharan haplotypes with Equatorial Guineans. The slave trade seems the most probable origin of the African haplotypes found in the Canary Islands.