The first aim for this paper was to examine gender and age differences in the intensity of usage of information and communication technology (ICT: computer for digital playing, writing and e-mailing and communication, and Internet surfing, and mobile phone). Second, we modelled the possible mediating role of sleeping habits and waking-time tiredness in the association between ICT usage and perceived health (health complaints, musculoskeletal symptoms, health status). The participants were 7292 Finns aged 12, 14, 16 and 18 years responding to a postal enquiry (response rate 70%). The results showed that boys played digital games and used Internet more often than girls, whose mobile phone usage was more intensive. Structural equation model analyses substantiated the mediating hypothesis: intensive ICT-usage was associated with poor perceived health particularly or only when it negatively affected sleeping habits, which in turn was associated with increased waking-time tiredness. The associations were gender-specific especially among older adolescents (16- and 18-year olds). Intensive computer usage forms a risk for boys', and intensive mobile phone usage for girls' perceived health through the mediating links. Girls were vulnerable to the negative consequences of intensive mobile phone usage, as it associated with perceived health complaints and musculoskeletal symptoms both directly and through deteriorated sleep and increased waking-time tiredness. The results of gender-specific ICT usage and vulnerability are discussed as reflecting gendered psychophysiological, psychological and social developmental demands.