The deceased identified as Udairam Jat (35), daughter Kumari Raveena (6) and son Subhash (10) consumed poisoned in their home in Vagatpura town of Rajsamand district last night, police said.
The bodies of the deceased were found in a room and a bottle of poison was recovered from the site, they said.
Udairam's wife had gone to her in-laws' house a few days ago, they said adding she has been informed about the incident.
The reason behind the suicide is yet to be ascertained and the bodies have been sent for post mortem, they said.