When the House met for the day, Ansari mentioned about the passing away of Sewak on July 28 at the age of 85.
An advocate by profession, Sewak worked for welfare of the weaker sections of society and eradication of untouchability.
A three-term Lok Sabha member, Sewak also represented the state of Uttar Pradesh in the Upper House for two terms - from July 1980 to July 1986 and from July 1986 to July 1992.
"In passing away of Chowdhary Ram Sewak, the country has lost an able parliamentarian and a dedicated social worker," Ansari said.
Members observed silence in memory of the departed soul.