The present studies on the biochemical composition and heavy metal analysis in catfish, Rita rita from River Indus near Jamshoro, Sindh, Pakistan was initiated from January 2015 to December 2017. The biochemical analysis was determined in terms of moisture, protein, lipid, carbohydrate and ash from two groups small and large from 10.1 to 20.0 and 30.1 to 40.0 cm respectively and from three body parts like head, trunk and tail region of male and female of catfish Rita rita during summer and winter. The moisture content of male was noted 88.05, 85.54 and 82.30 and 85.35, 83.10 and 84.62 in head trunk and tail region and in small and large group respectively during winter. In summer the moisture values were 86.75, 84.52 and 83.35and 81.05, 80.70 and 80.20 in head trunk and tail region and in both length group respectively. In case of female the values were 88.40, 82.0 and 81.80 and 85.0, 80.6 and 82.60 and 80.50, 81.0 and 81.0 in head, trunk and tail region and groups respectively in winter and summer. In the present study the protein content in male was noted 5.54, 2.58 and 4.27 and 3.37, 3.1 and 3.65 in head, trunk and tail region in small and large group respectively in winter. The values of protein in summer were 13.3, 9.0 and 8.5 and 11.0, 7.4 and 9.45 in different regions respectively and from both groups. The values in female were 4.89, 2.63 and 2.63 and1.23, 0.28 and 1.28 in three regions and from small and large group respectively during winter. In summer protein values were 12.9, 9.2 and 9.25 and 10.1, 6.7 and 10.60 in head, trunk and tail respectively. Lipid content in male 0.8,0.5 and 0.38 and 0.11,1.13 and 0.38 in head trunk and tail region in small and large group respectively during winter and in summer values 5.05, 4.03 and 2.08 and 7.0, 8.4 and 5.55 in regions from both groups respectively. The female contains 0.6, 0.2 and 4.25 and 1.29, 0.86 and 0.36 in various regions of small and large group respectively. The values of carbohydrate content in both the sexes and in seasons did not show any significant difference at different length groups. It was observed that ash content in male 5.53,13,44 and 12.36 and 10.0, 11.58 and 14.85 in different region small and large group during winter in summer 1.55, 2.8 and 2.5 and 2.4, 3.75 and 2.96 in head trunk and tail region of both groups respectively. The ash content in female was 6.42, 12.16 and 10.5 and 12.26, 17.2 and 14.85 in different regions of both groups in winter during summer1.6, 3.0 and 2.6 and 2.54, 3.95 and 3.0 in different body regions of the groups.Finally it was noted that the head region found to be more nutritious in terms of protein content in both sexes and during summer and winter in comparison to trunk and tail region. For heavy metals analysis of Rita rita in the present study from River Indus near Jamshoro was based upon the determination of iron, zinc, chromium, copper, manganese and cobalt from gills liver and kidney of both the sexes. The iron concentration in male was found highest in liver (12.92 µg/g) followed by kidney (7.77 µg/g) and lowest in gill (3.83 µg/g) in small fish group and similar trend was noted with highest values in liver (3.76 µg/g) followed by kidney (2.04 µg/g) and lowest in gill (1.91 µg/g) in large fish group. In case of female highest amount was from liver (3.16) followed by kidney (2.85 µg/g) and lowest from gill (2.33 µg/g) in small fish group while similar trend was noted in liver (4.44 µg/g) followed by kidney (3.83 µg/g) and lowest in gill (3.73 µg/g) in case of large group. The zinc concentration was found highest in liver (0.83 µg/g) followed by gill (0.49µg/g) and lowest in kidney (0.33 µg/g) in male of small group, similar highest values were found in kidney (2.01µg/g) followed by gill (0.72 µg/g) and lowest in liver (0.55µg/g) in large group. In case of female the highest amount of zinc was obtained from kidney (0.39 µg/g) followed by liver (0.30µg/g) and lowest in gill (0.15 µg/g) in small group the same ratio of concentration of zinc were found in kidney (0.49µg/g) followed by liver (0.42 µg/g) and lowest in gill (0.34 µg/g) in large group. The chromium concentration was found high in gill (1.35µg/g) followed by liver (1.15µg/g) and lowest in kidney (0.13 µg/g) from male in small group in case of large group the highest values were found in liver (0.28 µg/g) followed by kidney (0.28µg/g) and lowest in gill (0.27µg/g). In female the highest amount was found in kidney (0.90 µg/g) followed by liver (0.22µg/g) and lowest in gill (0.04 µg/g) in small group and also similar trend was noted in large group highest in kidney (1.23µg/g) followed by liver (0.32 µg/g) and lowest in gill (0.09µg/g). Copper concentration was found highest in gill (1.35µg/g) followed by liver (1.15µg/g) and lowest in kidney (0.06 µg/g) in male at small group in large group the highest were recorded from liver (0.28 µg/g) followed by kidney (0.28µg/g) and lowest in gill (0.28µg/g). In case offemale the higher amount was noted in kidney (0.33 µg/g) followed by liver (0.18µg/g) and lower amount from gill (0.13 µg/g) in small group in large group the higher values were in kidney (0.41µg/g) followed by gill (0.28 µg/g) and lower in liver (0.20µg/g). The manganese concentration was found highest in gill (0.35µg/g) followed by liver (0.16µg/g) and lowest in kidney (0.05 µg/g) in male of small group and similar trend was noted in large group (0.39 µg/g), (0.06µg/g) and (0.02µg/g) in gill, liver and kidney respectively. In case of female highest amount of manganese was recorded in gill (0.20µg/g) followed by kidney (0.10µg/g) and lowest in liver (0.05µg/g) in small group and similar trend was noted in large group highest values were found (0.30µg/g), (0.12µg/g) and (0.07µg/g) in gill, liver and kidney respectively. The cobalt concentration was found minimum quantity in all organs of male and female and small and large group of R. rita in present study. It was observed that the liver was found with high values of heavy metal concentration at small and large group of both sexes as compared to kidney and gill. The determination of heavy metal concentration from River Indus did not show any significant variation during summer winter, the values of metals concentration was found to be within the suitable ranges as recommended by WHO (2010). Finally it was concluded that the head region of experimental fish R. rita from River Indus near Jamshoro found to be nutritionally rich in term of protein content as compared to trunk and tail region. The liver was found to be more affected then that of kidney and gill in present study but the values of heavy metals concentration obtained from River Indus during the present course of investigation was found to be in permissible limits.