Three types of dissociated misfit dislocations (MDs) in epitaxial Ba0.3Sr0.7TiO3 thin films grown on (001) LaAlO3 have been studied by high-resolution transmission electron microscopy. First, a MD with b= dissociates into two edge partials and results in the incline of film lattice. Second, a  MD is split into two (1/2) partials of mixed character. In the third case, a  MD of mixed character is composed of three partials which are reacted with two (1/2)<110> stacking faults. Neither of the three types of dissociation reactions has been reported before for MDs in perovskite thin films.