Background & Aim: Implant therapy is highly recommended treatment modality for completely edentulous patients especially those with loose dentures with poor fit. Since implant therapy is a surgical process and involves lot of bio-mechanics and aftercare, complications are very commonly seen. These may be related to implant or prosthesis or both. This study was conducted to assess various post operative complications in patients rehabilitated with implant supported overdenture. Materials and Methods: In this study, both male and female patients were included. Inclusion criteria were edentulous patients wearing implant supported mandibular overdenture. Patients with any systemic problem or loss of follow-up were strictly excluded from the study. Both bar and ball supported mandibular implant overdentures were analyzed in detail for evaluation of different complications. Ball supported mandibular implant overdentures were in group 1 of 20 patients while bar supported mandibular implant overdentures were in group 2 of 20 patients. P value less than 0.05 was taken as significant. Statistical Analysis & Results: Statistical analysis was completed by using software SPSS. In the first age group of 50-55 years, total 9 patients were noticed. P value was highly significant for this group. In group 1, mean of housing failures was 6.41 with 0.928 standard deviation and 0.835 standard error. P value was highly significant here (0.01). Mean of ‘O’ ring loosening was 5.22 with 0.322 standard deviation and 0.429 standard error. In group 2, mean of clip breakage was 8.41 with 0.486 standard deviation and 0.945 standard error. P value was highly significant here (0.02). Mean of clip loosening was 7.36 with 0.622 standard deviation and 0.609 standard error. Statistical comparison among the 2 study groups using one-way ANOVA revealed significant p value (0.001). Conclusion: Authors concluded that in ball supported mandibular implant overdentures, housing failures and O ring issues are highly frequent. Likewise in bar supported mandibular implant overdentures, clip breakage and associated loosening were most common problems in post operative phases. Hygienic issues were very sporadic in both the studied groups.