Kumari represented India at the 2004 Summer Olympics. She placed 43rd in the women's individual ranking round with a 72-arrow score of 620. In the first round of elimination, she faced 22nd-ranked Kristine Esebua of Georgia. Kumari pulled off a surprising upset, defeating Esebua 153-149 in the 18-arrow match to advance to the round of 32. In that round, she faced Bhutanese archer Tshering Chhoden. Kumari won the match in a 7-4 tie-breaker after a 134-134 tie in the regulation 18 arrows, advancing to the round of 16. She then lost to 6th-ranked Yuan Shu Chi of Chinese Taipei 166-148, finishing 15th in women's individual archery.
Kumari was also a member of the 8th-place Indian women's archery team.
- "Ready, Aim, Aspire..." India Today. 9 August 2004. Retrieved 6 February 2010.
- "Reena Kumari". sports-reference.com. Archived from the original on 18 April 2020. Retrieved 6 February 2010.
- "Indian women lose narrowly". The Hindu. 21 August 2004. Archived from the original on 24 August 2004. Retrieved 6 February 2010.