The relationship between the rate of modern contraception and unintended pregnancy is complicated in Tanzania. Although the contraception rate has been slightly increased; the unintended pregnancy rate has remained at 2224% since 1999. In addition, married women in rural areas use less modern contraceptive methods than those in urban areas. Young women are at a higher risk of mistimed and unintended pregnancy compared to older females. Various barriers to using contraceptive methods have been reported, including fear of side effects, lack of knowledge, misconception, accessibility of the methods, and limited health workers' skills. This study was aimed to invest the barriers to using modern contraceptive methods among rural young married. A qualitative study was carried out in Moshi rural district in northeast Tanzania between June 2019 and July 2019. 22 in-depth interviews (9 key informants and 13 young married women aged 19-34) were conducted. Thematic analysis was used and data transcripts were coded. As a result, all participants were familiar with modern contraceptive methods and experienced at least one of them. Fear of side effects and prefer inappropriate birth control methods especially superstitious methods were major barriers to use. Also, rumours and misleading concerns have arisen from peers and village members. Condoms were not used among them, and males and the elderly still perceived family planning negatively. Additionally, although long-term modern contraceptive methods have been increased and preferred, IUCD is inaccessible due to the lack of skilled workers and facilities. In conclusion, community-based reproductive education is required to increase awareness of safe and reliable modern contraceptive methods. And frequent outreach services of the field are essential to provide more contraception's benefits to the village members so that barriers to using contraception and unwanted pregnancy could be reduced in rural Tanzania. In order to do that, more interventions, such as NGOs and strengthened government systems of reproductive health, should be enhanced.