An experimental study was conducted to assess marginal adaptation of various bulkfill composite materials, at cervical and occlusal margins of class II cavity preparation, applied by two different application techniques. Seventy-two (72) extracted premolar teeth were selected, prepared and filled with three different bulkfill composite materials, and inserted using incremental and bulk techniques. Specimens were thermocycled and bisected mesio-distally. All specimens were observed using a confocal fluorescence imaging microscope at 10× magnification. The data was analyzed using the Mann-Whitney U test. P < 0.05 was used to indicate statistically significant differences. The study results revealed that, no significant differences in marginal adaptation were detected among the two application techniques (incremental and bulkfill) at cervical margins p=1.000 and the occlusal margins p=0.639 with the lowest gap width formation achieved by X-trafil® bulkfill composite among the three different bulkfill composite filling materials, while Filtek^TM Flowable composite material had the highest gap width. This study signifies that good marginal seal depends on the proper cavity preparation, good manipulation of filling materials and skill of the operator whatever is the application technique.