Introduction: Prostate cancer (PCa) remains one of the most common causes of cancer deaths in men worldwide. While PCa can be deadly, 93% of men diagnosed will survive for at least 5 years, and 72.1% will survive for at least 10 years. Due to slow-growing nature of PCa, the life span of PCa patients is long. The longer the life span, the longer the time patients have to deal with disease and treatment-related side effects. The functional assessment of cancer therapy-prostate (FACT-P) questionnaire is a validated questionnaire for the evaluation of the quality of life (QOL) in PCa. We studied the QOL using a FACT-P questionnaire in different stages of PCa in an Indian setup. Materials and methods: This was a prospective observational study. Patients with carcinoma prostate at various stages of presentation were included over a period of 18 months. Patients were assessed with the FACT-P questionnaire in the form of an interview where questions were read, and responses from the patients were recorded. The interview was conducted both before and at least 3 months after the initial definitive treatment of management. The trial outcome index (TOI), functional assessment of cancer therapy-general (FACT-G), and FACT-P composite scores were calculated from the patient responses for various intragroup and intergroup comparisons. The localized prostate cancer (LCaP) cohort was subgrouped into low-risk (LR), intermediate-risk (IR), and high-risk (HR) groups as per D\'Amico risk stratification. The metastatic patient cohort was subgrouped into oligo and non-oligometastatic groups. Results: We included 63 patients with 26 LCaP, 10 locally advanced (LACaP), and 27 metastatic (MCaP). There were statistically significant differences in all three QOL indices, namely TOI, FACT-G, and FACT-P, before and 3 months after definitive therapy in all three stage categories. There were no differences in the QOL indices before treatment, in LCaP and LACaP, while the QOL indices differed significantly across all other intergroup comparisons, namely LCaP vs LACaP after treatment, LACaP vs MCaP both before and after treatment, and LCaP vs MCaP both before and after treatment. There were differences in TOI, FACT-G, and FACT-P scores before and after treatment in all the Gleason\'s grade groups (GG). Post hoc analysis showed that the differences were primarily between the GG-I and GG-V in both before and after treatment phases. Subgroup analysis showed a significant change in QOL scores in IR, HR, and oligo and non-oligometastasis groups 3 months after treatment. On post hoc analysis, it was found that the LR and LCaP patients had significantly better QOL indices than the HR before the LCaP treatment phase. The rest of the intergroup comparisons were not significant. Conclusion: We conclude that QOL in patients of PCa significantly improves with treatment at all stages of the disease, although it is poor in higher stages and grade at presentation. A larger cohort with a longer follow-up is needed to validate our findings.