The main economic activities of the people of Njombe include cultivation of food crops.
Njombe was one of the largest producers of Irish Potatoes, Maize and partly beans.
As for cash crops, timber and electric poles are produced at large amounts.
The common tree species grown here include Pines at a very large percent and a little of Eucalyptus and Cypress.
As of 2002[update], Njombe District was administratively divided into twenty-five wards: