Objective: to describe the norms and perceptions of a sample of Spanish parents and guardians on the use of mobile devices (smartphone and/or tablet) by their children and their association with such use. Method: a quantitative, analytical, cross-sectional, online, exploratory study was conducted with a non-probability sample of parents or guardians of children using smartphones or tablets. The virtual questionnaire consisted of 44 questions and was available at https://www.kenkolab.org/participa/. Results: the total number of participants (parents or guardians) was 183 people. It was observed that 26.2% of parents admitted that their children had free and unrestricted access to smartphones or tablets. Associations were identified between time spent using mobile devices and parental attitudes, such as permission without time limitation and use as a reward or punishment. Approximately half of the respondents believe that their children use the mobile device longer than recommended. Conclusion: most parents exercise some control over their children's use of devices. Acting on parental norms and perceptions is vital to success in addressing children's time spent on mobile devices. Community nursing could be a vehicle for education in healthy screen consumption habits in early childhood.