The structures of Ga3N, GaN3, Ga3N2 and Ga2N3 clusters are studied using the full-potential linear-muffintin-orbital molecular dynamics (FP-LMTO MD) method. Four structures for Ga3N, five structures for GaN3, nine structures for Ga3N2 and nine structures for Ga2N3 have been obtained. The most stable structures of these clusters are planar ones. A strong dominance of the N-N bond over the Ga-N and Ga-Ga bonds appears to control thestructural skeletons, supporting the previous result obtained by Kandalam and co-workers. The most stable structures of these small GaN clusters displayed semiconductor-like properties through the calculation of the HOMO-LUMO gaps.