Infinite dimensional representations of Type I Lie superalgebrasl(m/n) for which the highest weight is singly or multiply and diagonally atypical are shown to have a character formula which is a modified version of the Bernstein-Leites character formula. This formula is also shown to be valid for all infinite dimensional representations of the Lie superalgebraC(2) classified according to the atypicality type of the highest weight A