In view of the high incidence of canine cutaneous atopic disease and the relevance of mast cells to its pathogenesis, it was considered important to isolate firstly cutaneous mast cells from normal dog skin and to assess the histamine secretory activity, as this can be further used as a tool for the study of canine skin mast cell pharmacology in cutaneous atopy. The procedure for canine dermal mast cell dispersion following a skin enzymatic digestion (as for previous human skin mast cell dispersion methods) is described in detail. The number of canine cutaneous mast cells yielded per gram of skin was 2.31 ± 0.21 × 105 representing 1.00% of the total cutaneous cells. The total histamine content per mast cell is 4.93 ± 0.39 pg. Net histamine release owing to stimulation by calcium ionophore A23187 (1 μM) and concanavalin A (1 mg ml-1) was respectively 32.17 ± 3.56% and 20.39 ± 2.41% of the total amount per cell. Viability and reactivity to both stimuli of dispersed cutaneous mast cells were similar to the results found in humans. The present study allows further research on the role of mast cells immunopharmacology in allergy by investigation of cells isolated from canine skin in naturally occurring or experimentally induced atopy in the dog to be undertaken. © 1993.