Introduction: One of the important techniques for prevention of dental caries is the application of pit and fissure sealants. The sealant success depends on not only adhering firmly to the enamel surface, but also isolation of pits and fissures from the rest of the oral environment. The study was conducted to evaluate and compare three pit and fissure sealant materials for viscosity, microleakage, and resin tag length. Materials and methods: Sixty premolars were selected for the study. The teeth were randomly divided into three groups. Group I: type VII GIC, group II: Delton FS, group III: Delton. Teeth were prepared by pumice prophylaxis and etched with 37% phosphoric acid. The respective pit and fissure sealants were applied. Teeth were stored in 1% methylene blue dye and sectioned mesiodistally into two halves. The microleakage was assessed using stereomicroscope and resin tag length using scanning electron microscope (SEM). Brookfield's viscometer was used to measure the viscosity. Result: Viscosity was lowest for Delton and highest for type VII GIC. Microleakage was seen least with the Delton (0.0%) sealant, followed by Delton FS (20.0%), and highest in Type VII GIC (85.0%) in the scoring criteria of 3 and 4 and the mean length of the resin tags was least for Type VII GIC was 3.79 ± 2.58 µm, followed by Delton FS was 5.60 ± 2.12 µm, and highest for Delton was 7.27 ± 3.43 µm. The relation between viscosity, resin tag length, and microleakage was negative. As the viscosity gets lower, the more long the resin tags formed and the microleakage decreased. Delton pit and fissure sealant had lowest viscosity and microleakage scores while longest resin tag lengths. Conclusion: Delton with the lowest viscosity and microleakage appears to be a more suitable pit and fissure sealant compatible with residual moisture and ideal for use in children, where isolation is a problem.