This study was conducted during May to September in 2012 to investigate the distribution and diversity of beetles in Mt. Jangsan (634 m) located near Busan, Republic of Korea. The collection of beetles was repeated 11 times in the four areas classified according to altitudes 200 m, 400 m, 600 m, and over 600 m (approximately) on the south and north slopes of Mt. Jangsan. A total of 12 families, 20 species, and 4,343 individual beetles were collected. In the southern slopes, a total of 12 families, 20 species, and 2,264 individuals were collected, whereas a total of 12 families, 20 species, and 2,079 individuals on the northern slopes were captured. The monthly emergence of beetles was the highest in August at 651 individuals followed by 516 individuals in September, 496 individuals in July, 364 individuals in Jun, 237 individuals in May. In the northern slopes, the monthly emergence of beetles was the highest in August as 591 individuals followed by 512 individuals in September, 443 individuals in July, 321 individuals in June, and 212 individuals in May. On the southern slopes, the species diversity index, evenness index, and dominance value were 0.950, 0.730, and 0.181, respectively, while in the northern slopes, the species diversity index, evenness index, and dominance index were 0.946, 0.727, and 0.182, respectively. In the both slopes, the species diversity index and evenness index were the highest in May, while dominance index was the highest in September. This study lays the groundwork for further monitoring of these sites and others through the region for environmental changes using the indicator species.