Once abundant with trees that provided wood for furniture-making, the natural vegetation in the city has been reduced to rows of full-grown acacia trees lining the shoulders of Acacia Lane and spare stands of trees in private lots, subdivisions and school compounds.

Urban forestry has been introduced along sidewalks and center-island of roads, in spare yards around public buildings and pocket and linear parks along Pasig River. These cultivated vegetation are mostly ornamental plants, a few fruit-bearing trees and flowery shrubs.

Wack-Wack, home to an 18-hole golf course, is covered in green ornamental grass and cultivated trees.

There are no record of fauna species in Mandaluyong except for domesticated animals such as dogs and cats and other household pets like rabbits, white mice and love birds. Common birds and insects could also be found in the periphery such as maya, a variety of butterflies and other garden insects.

Common species of fish can be found in the Pasig River such as the janitor fish, kanduli, gurami, etc. However it is not ascertained whether these are edible considering probability of lead content and other toxic chemicals on these fishes.