Neonatal patients are particularly appropriate for utilization of diagnostic exome sequencing (DES), as many Mendelian diseases are known to present in this period of life but often with complex, heterogeneous features. We attempted to determine the diagnostic rates and features of neonatal patients undergoing DES. The clinical histories and results of 66 neonatal patients undergoing DES were retrospectively reviewed. Clinical DES identified potentially relevant findings in 25 patients (37.9%). The majority of patients had structural anomalies such as birth defects, dysmorphic features, cardiac, craniofacial, and skeletal defects. The average time for clinical rapid testing was 8 days. Our observations demonstrate the utility of family-based exome sequencing in neonatal patients, including familial cosegregation analysis and comprehensive medical review.