The Tories raked in over £5 million from significant donations in the final quarter of last year – nearly double the sum received by Labour.
David Cameron's party was handed £5.15 million compared to £2.67 million for the Opposition, according to Electoral Commission figures.
Some £2 million of Labour's gifts were from unions – including around £940,000 from Unite and £353,000 from Unison.
However, the party's income was topped up with £1.5 million of public funding, while the Conservatives received £303,000.
The Liberal Democrats declared £828,000 of gifts, and Ukip topped up £196,000 of donations with nearly £90,000 of public funding.
The SNP received £347,000, including £293,000 from the taxpayer.
The British National Party (BNP), which temporarily lost its status as a political party last month after omitting to pay a £25 registration fee, benefited from a £150,000 bequest.
The details cover donations of more than £7,500 accepted by parties between October and December 2015.