The reporting of complications following transperitoneal and retroperitoneal open radical nephrectomy (RN) is nonstandardized. This study aimed to compare early complications between the two approaches using a standardized reporting methodology in a large contemporary cohort. Between 1996 and 2009, 558 patients underwent open RN for renal cell carcinoma (RCC) in our two centers (424 from Sun Yat-sen University Cancer Center and 134 from the First Affiliated Hospital of Sun Yat-sen University). Records were reviewed for clinicopathologic features and complications. Complications were graded using the Clavien system based on the severity of impact. One hundred and five patients (18.8%) had one or more early complications (168 complications overall). The overall rates of grades I to V complications were 5.6%, 10.8%, 2.2%, 0.4%, and 0.2%, respectively. Patients who underwent transperitoneal RN did not experience more overall or procedure-related complications than those who underwent retroperitoneal RN (P = 0.911 and P = 0.851, respectively). On subgroup analysis, neither grade I/II nor grades III-V complications were significantly different between the transperitonal RN and retroperitoneal RN groups. Multivariate analysis showed that for any grade of complication, age (P = 0.016) and estimated blood loss (P = 0.001) were significant predictors. We concluded that open RN is a safe procedure associated with low rates of serious morbidity and mortality. Compared with retroperitoneal RN, transperitoneal RN was not associated with more complications. Older patient and more blood loss at surgery were independent predictors for higher early postoperative complication rates.