This study was conducted to evaluate the retention, marginal adaptation, marginal discoloration and presence of caries of self-adhesive and conventional flowable composites used as pit-and-fissure sealants in mandibular first permanent molars(in vivo study). A total number of 30 children were included. Their ages ranged from six to eight years. According to the circumstances ofthis study, it was concluded that both materials (Vertise Flow and Tetric N-Flow) demonstrated acceptable clinical performance as fissure sealants and caries prevention in permanent molars.