The main objective of the present study was to investigate the relationships between Problematic Internet Use (PIU) and time spent online, online activities and psychopathology, by taking cross-cultural and gender differences into account. The second objective was to provide the prevalence estimate of PIU among European Internet users. Our total sample consisted of 5593 Internet users (2129 men and 3464 women) of nine European countries, aged between 18 and 87 years old (M = 25.81; SD = 8.61). Recruited online, they completed several scales about their Internet use and psychopathology. PIU was related to time spent online at weekends, obsessive-compulsive symptoms, hostility and paranoid ideation among the total sample of women; among men phobic anxiety was also significant. Regression analyses performed in each sample also suggest the importance of obsessive-compulsive symptoms (in seven samples), somatization (four samples) and hostility (three samples). Many cross-cultural and gender differences have been observed in terms of relationships with psychopathology and online activities. Prevalence estimates of PIU ranged between 143% and 54.9%. PIU was more prevalent among women in the respective samples, including the total sample. This European research highlights relevant relationships between PIU, psychopathology and time spent online, as important differences with regards to these variables in respective samples. This study's cross-cultural design also allows a better understanding of gender differences in PIU. (C) 2018 Elsevier Ltd. All rights reserved.