Seasonal deviations in proximate composition and intramuscular profile of fatty acid of one of the prolific specie of fish Labeo rohita in Indus River, Pakistan, were studied. The lipid content was significantly higher (p<0.05) in spring (1.95%) followed by winter (1.36%), autumn (0.98%) and summer (0.95%). Protein fluctuates directly with lipids, highest percentage was observed in spring 23% while lowest in summer 20%. As compared to other seasons, higher contents of moisture (75.65%) were found in summer, whereas more plentiful nutrients were available in the spring, which cause an increase in the amount of parched material therefore decrease in the moisture content (72.91%) was observed. In all sampling seasons, in fish oil the most abundant fatty acids were palmitic acid (16:0), oleic acid (18:1), n-3 eicosapentaenoic acid (EPA 20:5) and n-3 docosahexanoic acid (DHA 22:6). The sum of polyunsaturated fatty acid (PUFA) was 42% in spring, 37% in winter, 36% in autumn and 32.02% in summer. In the total fatty acids the levels of DHA in spring, winter, autumn and summer were16.63%, 15.71%, 15.12%, 13.05% and while those of EPA were 4.35%, 5.52%, 4.59% and 5% respectively. During all seasons the total n-3 fatty acid was found higher in contrast to n-6 fatty acid. The highest ratio of n-3/n-6 was recorded during winter 1.84, while PUFA/SFA ratio was found higher in spring 2.33.