This study aimed to examine the relationship between social and emotional loneliness and the use of modern technologies in a sample of young people in emerging adulthood. The second aim was to describe the Internet habits of young people, and the difference in loneliness and attachment to the mobile phone was investigated regarding the gender and age of the participants. There were 211 participants in this study, who completed the Social and Emotional Loneliness Scale (SELSA; DiTomasso and Spinner, 1993), The Mobile Phone Attachment Scale (MAS; Konok et al., 2016), and answered questions about their internet use. An online survey was used to collect data. The invitation to participate was distributed via social media platforms and personally with a request to forward it to other colleagues who belong to the same age group (age 18 to 25). Results show that there are statistically significant, positive correlations between the total level of loneliness and the total time spent on the Internet, as well as various Internet activities, but these correlations are relatively low. Research findings suggest that the association between loneliness and attachment to a mobile phone is extremely low and insignificant. It was also determined that young women are significantly more attached to mobile phones than young men and that there is no difference in the level of attachment to mobile phones regarding the age of the participants. Significant differences were found in the level of loneliness regarding the gender of the participants, in such a way that young men are significantly lonelier in love and socially lonelier than young women. It was also shown that participants aged 23–25 are significantly less lonely in love than younger research participants, while no age-related differences were found in the remaining types of loneliness. Given that research by other authors indicates that in the last few decades there has been an increase in various forms of loneliness among young people, the results of this research can give a clearer picture of loneliness in that age group and its relationship with the use of new technologies.