The Cause of Death Registry data are derived from death notification forms (DNFs). These data are used to formulate mortality statistics that are used in the development of health systems and in public health planning. This study assessed the quality of registered data in DNFs in Gaza to form a basic understanding of the current situation, and with a view to providing evidence-based recommendations to improve data quality. In 2016, the Ministry of Health issued 4861 DNFs in the Gaza governorate. A representative sample of 509 DNFs was selected using proportional systematic random sampling. A set of indicators was identified using the WHO guidelines for DNF data quality assessment. 13 data items were identified to represent administrative data plus nine items to represent medical data, and a total score for completeness was calculated. The quality of medical data was examined by a doctor trained to analyse the quality of mortality data. Administrative approval was obtained from the Ministry of Health. The assessment did not include any personal data (and all data were anonymous). The completeness of administrative and medical data was 89·0% (5500 of 6180) and 47·3% (2168 of 4581), respectively. For the underlying cause of death, completeness was 36·5% (186 of 509). The completeness of ICD-10 coding was 46·8% (238 of 509) for the direct cause of death and 12·6% (64 of 509) for the underlying cause. Only 23·0% (three of 13) of DNFs for women of reproductive age indicated whether the woman was pregnant or not and whether her death was related to maternal health problems. The ICD-10 codes with the written cause of death were checked and the ICD-10 documentation was correct in 58·0% (138 out of 238) of DNFs for the direct cause of death and 67·2% (43 out of 64) of DNFs for the underlying cause of death. The completeness and accuracy of medical data in DNFs is low. There is an urgent need to train physicians and medical interns to give the correct death sequence and ICD-10 codes, particularly for the underlying cause of death. None.