Smartphones allow their users accessibility to internet, media, games and social networks. Nowadays, in modern life many people prefer to contact via smartphones. Beneath the potential benefits of smartphones, related harms as problematic use or 'addiction” should also be considered especially among young adults.

To determine smartphone addiction in relation with social anxiety and loneliness among university students.

Three hundred sixty-seven students who have a smartphone in an university in Istanbul participated in the study. The participants were given a set of questions about their style of smartphone use, Smartphone Addiction Scale-Short version (SAS-SV), UCLA Loneliness Scale and Brief Social Phobia Scale.

Significant difference was found between users who declare their mainly purpose to use a smartphone as access to social network sites and who declare it as access to internet or a phone call (p<0.001). Addictive tendencies were negatively correlated with the age of owning the first mobile phone. Scores in total and all subscales of Brief Social Phobia Scale are positively correlated with SAS-SV scores in both sexes. Scores of UCLA Loneliness scale were also positively correlated with SAS-SV scores in female students.

Findings of this study suggest that smartphone users who have their first mobile phone in an early age and who use their smartphone primarily to access social network sites have an addictive use of smartphone. Also social phobia in both sexes and loneliness in females make smartphone users more prone to an addictive usage of smartphones.