Objectives: This study aimed to investigate the bristle tip morphology of toothbrushes sold in the Korean market. Methods: Tufts were taken from each of the 69 different toothbrushes that were selected. The bristle specimens thus prepared were observed under a phase-contrast microscope. The images taken by the microscope were then classified as round, tapered, or mixed. The proportion of acceptable rounded-end bristles and tapered bristles was then determined. Results: Of the randomly selected 69 toothbrushes, 42 were domestic and 27 were imported. Of the domestic toothbrushes, the proportion of acceptable toothbrushes was 52.4%, whereas the corresponding proportion was 77.8% for imported products. In terms of classification based on tooth brushing techniques, 55.0% of all manual toothbrushes had round-ended bristles. Moreover, based on classification by age, 67.2% of the toothbrushes for adults were acceptable and 75.0% of tooth brushes for children were termed non-acceptable. Conclusions: The majority of toothbrushes sold in the Korean markets have acceptable bristles. However, not one toothbrush had 100% acceptable bristles. The manufactures should improve their manufacturing processes to produce bristles of the intended quality.