Wildlife on Liberia's coastal plain, where Monrovia is located, has been virtually wiped out by hunting and habitat destruction, including increased poaching during the prolonged period of political instability since 1990. The Society for the Conservation of Nature of Liberia (SCNL), headquartered in Monrovia, is primarily concerned with preserving Liberia's rain forests, located in the northwest and southeastern parts of the country. However, following the country's civil war, the society also mounted a major campaign in the capital to rehabilitate its zoo, spearheading extensive renovations intended to include a guest house and environmental education center on the zoo grounds. The SCNL also initiated a project to plant acacia seedlings at some 50 sites around the city.

Liberia's largest generating station, the Mount Coffee hydroelectric plant on the Saint Paul River, is located near Monrovia. About half of Liberia's electric energy comes from hydroelectric generation.

Pollution of the river by iron ore tailings is a growing problem, while purity of the waters off the Atlantic coast is threatened by untreated sewage and waste water and oil residues.