Some preliminary results of dislocation analysis and associated glide systems in as-grown as well as in superplastically deformed beta silicon nitride are presented. Transmission electron microscopy observations using the weak-beam technique, are reported. [000.1]{10 (1) over bar 0} and 1/3(1 (2) over bar 10){10 (1) over bar 1} glide systems have been characterized. In the basal plane, a superposition of two hexagonal networks built with screw dipoles has been observed. Both a sequence extended node-constricted node and partial dislocations have been identified in these networks which clearly evinces dislocation dissociation in beta-silicon nitride following the reaction 1/3[2 (1) over bar (1) over bar 0] --> 1/3[10 (1) over bar 0] + 1/3[1 (1) over bar 00].