A statement from Vincent George, her secretary, denied media reports earlier in the day that she would contest her late husband's constituency, Amethi, in the northern state of Uttar Pradesh.
Earlier, the United News of India (UNI), quoting sources in the Congress Party unit of Uttar Pradesh, said the 51-year-old widow would file her nomination from Amethi today.
But Mr George said in a statement: "Mrs Sonia Gandhi's attention has been drawn to the report to the effect that she may contest the coming elections from Amethi. She has been overwhelmed by the affection and enthusiasm of the people of Amethi.
"While acknowledging her desire to deepen her relation with the constituency of her late husband she has decided that for now she will not contest the elections but will concentrate on campaigning for and strengthening the Congress Party throughout the country."
With her ties to leaders of India's past, Mrs Gandhi has been hailed as the saviour of the crumbling party since she agreed several weeks ago to break her seclusion to campaign. Although she has addressed several rallies, she has rejected repeated pleas from party leaders that she run for office and even take over the party as its prime ministerial candidate.
The ailing Congress Party is expected to finish well behind the Hindu nationalist Bharatiya Janata Party (BJP) in mid-term elections scheduled to take place over four days between 16 February 16 and 7 March.