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. 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. 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%). 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.