The aim of this cross-sectional study was to elucidate whether mindfulness was associated with relationship and/or sexual satisfaction among individuals in a regular relationship and to assess potential links with other factors. The research group consisted of 276 adults who were in a relationship regardless of marriage. Mindful Attention Awareness Scale (MAAS), Couples Satisfaction Index (CSI), New Sexual Satisfaction Scale (NSSS) were applied to all individuals. In the study group, 160 (58%) of the individuals were female, 116 (42%) were male, 62.3% were married, 59.8% were self-acquainted with their partner and 67.4% lived together with their partner or with their partner and children. Factors contributing to greater sexual satisfaction were shorter relationship duration and being a male, while those with an arranged marriage and those cohabiting with their partner had lower sexual satisfaction. Older age and, very interestingly, higher levels of mindfulness were associated with lower levels of relationship satisfaction. Finally, sexual and relationship satisfaction were closely associated and were respectively identified as independent factors for CSI and NSSS scores. There is a need for more comprehensive longitudinal studies evaluating relationship satisfaction and sexual satisfaction to assess causal relationships and to identify interventions that could benefit relationships.