The Irish firm reported a 1.8% rise in operating profits in Scotland for the year to the end of February.
But it said growth would have been stronger had it not been for "challenging trading conditions" in the final quarter.
It blamed the new drink-drive law, which came into force in December.
The legislation reduced the legal alcohol limit from 80mg to 50mg in every 100ml of blood.
C&C is the latest drinks firm to report an adverse effect on business.
Earlier this month brewer Greene King, which also operates pubs and restaurants across the UK, said sales would have been higher in its latest financial year had the legal limit not been changed.
Overall, C&C reported net revenue growth of 10.3% to Â£490m for the year, with operating profit down by 9.2% to Â£82.5m.
C&C said its Tennent's brand remained "in robust health" with a strong performance in both the on and off-trade sectors and in terms of exports, which rose by 37%.
The group increased brand investment on Tennent's and is planning a further increase in the next financial year.
It said other brands launched in recent years continued to "make good progress".
Caledonia Best sales grew 3.6% in the year, while its premium Belgian lager Heverlee saw volume growth of 116%.
Overall net revenue in Scotland increased by 61.4%, boosted by the acquisition of wines and spirits wholesaler Wallaces Express last year.
Stricter drink-drive legislation in Scotland has had an impact on profits for Tennent's lager maker C&C Group, according to the company.