Fiberglass is widely used for insulation and as a reinforcement filling material. Handling fiberglass products may induce contact dermatitis. We report on the first two cases of fiberglass dermatitis reported in Taiwan. The first patient suffered from a severe pruritic eruption two hours after repairing a roof with wave-form ceiling boards. Erythematous maculopapules were present on both hands and finger webs. The second patient was a quality controller of printed circuit boards (PRCBs). She presented with erythematous maculopapules on the face and excoriated papules and lichenified plaques on the trunk and forearms, which had been present for two years. Scrapings of the skin lesions from both patients showed fiberglass spicules of 7.5 to 8 microns in diameter. Similar fibers were detected in scrapings from the wave-form ceiling board and PRCB. Histopathology of the second case revealed spongiotic psoriasiform dermatitis. Patch tests in case 2 with the plastics and glues series, epoxy resin and scrapings from the PRCBs were all negative. Fiberglass dermatitis may be easily misdiagnosed. Clinically, it may resemble scabies, eczematous dermatitis, folliculitis, petechiae and urticaria. A high index of suspicion is essential for a correct diagnosis.