Mung bean has a well-developed root system. The lateral roots are many and slender, with root nodules grown.^[9] Stems are much branched, sometimes twining at the tips. Young stems are purple or green, and mature stems are grayish-yellow or brown. They can be divided into erect cespitose, semi-trailing and trailing types.^[9] Wild types tend to be prostrate while cultivated types are more erect.^[8]

Leaves are ovoid or broad-ovoid, cotyledons die after emergence, and ternate leaves are produced on two single leaves. The leaves are 6–12 cm long and 5–10 cm wide. Racemes with yellow flowers are borne in the axils and tips of the leaves, with 10–25 flowers per pedicel, self-pollinated. The fruits are elongated cylindrical or flat cylindrical pods, usually 30–50 per plant. The pods are 5–10 cm long and 0.4–0.6 cm wide and contain 12–14 septum-separated seeds, which can be either cylindrical or spherical in shape, and green, yellow, brown, or blue in color.^[9] Seed colors and presence or absence of a rough layer are used to distinguish different types of mung bean.^[8]