The Hamn gabbro pegmatites are found in mafic-ultramafic intrusion known as Hamn gabbro located on the Senja island, Northern Norway, about 100 km southwest from Tromsø. Geologically, Hamn gabbro belongs to 2.7-1.5 Ga West Troms Basement Complex. In gabbroic units 24 individual pegmatites are found, featuring no aplitic outer layer and internal zonation. The Hamn gabbro pegmatites contain three paragenesis: 1) Magmatic, 2) autometasomatic, and 3) post-magmatic - alteration assemblage. Labradorite, andezine, olivine, enstatite, pigeonite, augite, pargasite, Fe-Ti oxides and sulfides were formed by crystallization from the melt. Carbonates, zircon and apatite are accessory minerals. Autometasomatic reactions are responsible for symplectitic textures of Fe-oxide and enstatite from olivines. Chlorite, scapolite, saussurite, secondary clino- and orthoamphiboles, biotite and talc were formed by hydrothermal-metasomatic post-magmatic alterations from primary minerals. We propose that Hamn gabbro pegmatites were formed after separation of fluid phase from residual basaltic melt locally enriched in volatiles and fluxes, which was caused by the crystallization of anhydrous minerals. The gabbro pegmatites were crystallized simultaneously and in equilibrium with surrounding gabbroic rocks which confirms the absence of sharp contanct, mineral chemistry and trace elements distribution in both types of rocks.