The number of mobile applications (apps) related to health is increasing, and diabetes mellitus (DM) is not an exception. The aim of this study was to assess the free mobile applications for the management of diabetes available, in Spanish, in the Spanish market.GooglePlay (Android) and AppStore (iOS) were reviewed to identify free apps, in Spanish, aimed at people with diabetes. Their main functions and a series of quality and usability features were evaluated and scored. These scores were used to make a top list with the best apps.Out of 794 registered apps, 42 were evaluated and included in the quality assessment, while 34 apps were included in the usability assessment. The main function of most of the apps was to act as a blood glucose diary (n: 30; 71.43%). As for privacy, most of the applications (33 apps; 78.6%) access device/personal data. Only a minority of apps [3 (7.1%)] reported being based on evidence, and only 3 apps (7.1%) had a quality label. The top scored apps were: OneTouch Reveal™, Social Diabetes™, mySugr: App Diario de diabetes™, Diabetes menú™, Tactio SALUD™ and Diabetes:M™.There are few free apps for diabetes management available in Spanish, most lack quality certification and very few provide scientific references about their content. Furthermore, most of the apps access personal/device data.