The protesters led by Ms Fatima marched from Parivarta Chowk to Gandhi statue in Hazratganj, demanding justice for her son.
They also shouted slogans against Prime Minister Narendra Modi, Home Minister Rajnath Singh, BJP and RSS.
Mr Ahmad went missing from his hostel on October 15 last year.
Ms Fatima had yesterday appealed to student fraternity to help find her son saying that it has been nearly four months since he disappeared, but police was not able to trace him.
JNU office bearers also participated in the march.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.