PURPOSE: The prevalence of endocrine/genetic anomalies in boys with proximal hypospadias is unknown. We describe an endocrine/genetic evaluation for boys with proximal hypospadias to determine who may have a difference/disorder of sex development and/or benefit from additional testing. MATERIALS AND METHODS: We retrospectively reviewed boys with hypospadias seen at our hospital between January 2013 and October 2018. Those with proximal (penoscrotal, scrotal, perineal) hypospadias who presented before age 6 months and underwent endocrine/genetic testing were included. Demographics, test results, testicular examination at presentation, comorbidities and diagnoses were abstracted. RESULTS: A total of 1,789 boys with hypospadias were identified. Of 131 boys with proximal hypospadias all 60 who underwent endocrine/genetic evaluation were included. Most of these patients had bilateral palpable testes (52, 86%) that were fully descended (41, 68%). Associated anatomical anomalies were found in 53% of patients. All boys underwent endocrine testing, which was completely typical for a male infant in most (41, 68%). Common genetic tests included karyotyping (100%), microarray (38%) and multigene panel (13%). Genetic anomalies were found in 17 boys (28%), including 7 of 41 (17%) with bilateral descended testes and 10 of 19 (53%) with 1 or more undescended testes (p=0.01). Six of 8 boys with at least 1 nonpalpable testis had a genetic anomaly vs 11 of 52 with bilateral palpable testes (p=0.005). Differences/disorders of sex development were found in 9 patients (15%). CONCLUSIONS: Of 60 boys with proximal hypospadias 53% had nongenital anomalies, 28% had genetic anomalies and 15% had a difference/disorder of sex development. Although endocrine testing was clinically useful, genetic testing was most diagnostically revealing. Endocrine/genetic evaluation should be considered for boys with proximal hypospadias.