The present study evaluated the effects of stocking density on growth performance, survival rate, and haematological parameters rainbow trout (Oncorhynchus mykiss) fingerlings. An experiment was conducted for 8 weeks with different stocking densities including T1: 10 kg/m³, T2: 15 kg/m³, T3: 25 kg/m³ and T4: 35 kg/m³. After 8 weeks, the juveniles were randomly sampled and analyzed for growth indices including weight gain, survival, specific growth rate (SGR), feed conversion rate (FCR), and condition factor (CF) as well as haematological parameters including haemoglobin (Hb), haematocrit (Hct), mean crepuscular haematocrit (MCH), mean crepuscular haematocrit concentration (MCHC), and red blood cells (RBC). Treatments with higher density showed lower growth rates (SGR and weight gain) compared to those of lower densities. Highest survival rate was observed in T2 and the lowest in T4. Based on the results, the stocking density significantly affected Hct, Hb, and RBC (P<0.05), while MCH and MCHC were not significantly affected (P<0.05). The present study demonstrated that there is a significant negative effect of increasing rearing density on juvenile rainbow trout. Further, it is suggested 15 kg/m³ as an appropriate stocking density for rainbow trout fingerlings.