The seasonal variations of digestive diverticula in the scallop, Patinopecten yessoensis culturing by sowing method were studied by microscopic observations and individual measuring of the shells collected monthly from Abashiri Bay located in Hokkaido, Japan. Digestive diverticula index revealed the seasonal variations which showed the highest value in May and July, and the lowest value in December through April. The highest number of tubules per $mm^{2}$in the preparation of digestive diverticula was counted in March. But, in September and October the number of tubules decreased to the lowest value. The relationship between gonad index(X) and percent of lipid tubule(Y) as an indicator for the transference of lipid in digestive diverticula into the gonad was expressed by an exponential equation, $Y=145.6X^{-0793}$. It was suggested that the lipid in digestive diverticula showed the seasonal variations might be transferred into the gonad.