The agency benefited from its work on Carlsberg and Heineken's bid for rival brewer Scottish & Newcastle. It advised the target firm on the potential £10bn acquisition.
Smithfield also worked on the second biggest deal of January - advising Akzo Nobel on its £8bn bid for Imperial Chemical Industries.
Up one place in second spot sits FD, which advised on 16 deals, more than any other agency. Its headline deal was advising Scottish & Southern Energy on its £1.6bn acquisition of Irish wind power firm Airtricity.
Finsbury, which advised the bid team for the aforementioned Scottish & Newcastle deal, comes in third - up two places from last month.
Cardew Group is in fourth, followed by Brunswick, which topped last month's list. This month Brunswick advised Imperial Chemical Industries and also Reckitt Benckiser as it made a £1.1bn swoop for Adams Respiratory Therapeutics.
SVP Investor Relations & Corporate Communications advised Adams Respirtaory, placing it in sixth spot.
Citigate, advising on 11 deals, Waggener Edstrom, Threadneedle Communications and Equus round off the top ten.
Overall, January was very slow, with chiefs saying that IPOs and M&A deals in the offing had been held back while companies take stock of the moribund financial markets. Although figures were higher than last year, there were fewer deals, and values were propped up by the Scottish & Newcastle bid.
PRWeek is reviewing the Deal Watch round-up. As a result there will be no Deal Watch next month.