Malignancy is a well-known complication in patients after kidney transplantation (KT), but its effect on posttransplant outcomes, allograft, and patient survival remains unexplored. The aim of this study is to report the impact of the comorbidity on clinical outcome, function, and failure of an allograft kidney. This case-control study included 101 KT patients. Twenty-six patients who developed cancer (CA) were assigned to the case group and 75 to the control group. Statistical analysis was performed using logistic regression models, and graft survival was analyzed using the Kaplan-Meier curve. Non-melanoma skin CA was the most common malignancy, accounting for almost 60% of cases, followed by stomach CA, prostate CA, and lymphoproliferative diseases (7.70% each). Difference in graft and patient survival was not significant between the two groups (P > .05). A tumor in nonfunctioning in the first nonfunctioning KT was identified in 1 KT patient with a second allograft and by anatomopathological was detect Fuhrman grade II renal cell carcinoma. This KT patient was in good clinical condition with serum creatinine level of 1.5 mg/dL. No association was observed between CA development and risk factors, including family history and smoking habit, and no differences in allograft and patient survival were found. Nevertheless, in our data, CA in KT patients occurred early after transplantation. Renal cell carcinoma in allograft failure was identified in a patient; that suggested that nephrectomy of kidney failure must be performed to avoid patient allosensitization and neoplasia. Thus, we suggest continuous screening of malignancy diseases for KT patients.