To characterize the prognostic factors among pathological structural pattern, cell type, infiltration, and incidental or non-incidental renal cell carcinoma (RCC), we reviewed the records of 146 patients with RCC who underwent nephrectomy at our institute. The patients were 26 to 86 years old (mean age 58). The men-to-women ratio was 3.2:1. The tumor originated in the right kidney in 83 patients and in the left in 63. The solid pattern was associated with poorer survival than other patterns (p < 0.01). Spindle or pleomorphic cell type had poorer survival than common type (p < 0.01). The number of incidentally discovered RCC has increased since 1986, and survival is better than in non-incidental RCC, because of smaller tumor size, low stage tumor (stages 1, 2; 83.6%), and fewer papillary or solid type. In addition, there were no spindle or pleomorphic cell type, grade 3 or INF gamma-positive case. Survival is good even when the tumor is large.