We report the composition of constituent fatty acids and molecular species of adipose tissue triacylglycerols of male weaned Wistar rats fed diets containing, in addition to 20 g corn oil/kg feed, 120 g per kg feed canola-type rapeseed oil, olive oil or conventional sunflower oil for 10 wk. The composition of fatty acids and molecular species of the triacylglycerols of subcutaneous, epididymal and perirenal adipose tissues did not differ among groups (P>> 0.01), broadly reflecting the corresponding compositions of the dietary oils. The major molecular species of dietary triacylglycerols, especially trioleoylglycerol (OOO) and linoleoyl-dioleoylglycerols (LOO) in the rapeseed oil and olive oil diets, dioleoyl-palmitoylglycerols (OOP) in the olive oil diet, dilinoleoyl-oleoylglycerols (LLO) in the rapeseed oil and sunflower oil diets, and dilinoleoyl-palmitoylglycerols (LLP), linoleoyl-oleoyl-palmitoylglycerols (LOP) as well as trilinoleoylglycerol (LLL) in the sunflower oil diet were also prominent constituents of the corresponding adipose tissue triacylglycerols. On the other hand, predominant molecular species containing alpha-linolenoyl (Ln) moieties, e.g., alpha-linolenoyl-linoleoyl-oleoylglycerols (LnLO) and alpha -linolenoyl-dioleoylglycerols (LnOO) from the rapeseed oil diet were not prominent constituents of rat adipose tissue triacylglycerols, whereas LOP from rapeseed oil and olive oil diets and OOP from rapeseed oil and sunflower oil diets were distinctly enriched in the corresponding adipose tissues. Most of the minor molecular species of the dietary triacylglycerols from all the three diets were distinctly present in the corresponding adipose tissues. Thus, despite numerous biochemical processes involved in the metabolism of dietary triacylglycerols, a substantial proportion of the molecular species of adipose tissue triacylglycerols containing linoleoyl (L), oleoyl (O) and palmitoyl (P) moieties resemble those of dietary triacylglycerols.