* Q1 EPS ex-items 47 cents vs Street view 42 cents
* Sales $691.4 mln miss Street estimate of $703.8 mln
* Shares down 3.4 pct
May 8 (Reuters) - Molson Coors Brewing Co reported lower-than-expected quarterly sales on Tuesday, hurt by losing some market share in Canada, helping to send the beer maker's shares down more than 3 percent.
Unlike larger rivals Anheuser-Busch InBev and SABMiller Plc, Molson's business is concentrated in Canada, Britain and the United States, so weakness in one of those markets can cause worry.
The maker of Molson Canadian, Coors Light and Blue Moon beers lost half a point of market share in Canada in the quarter, as its sales to retailers fell 0.5 percent amid industry growth of 1.3 percent.
Still, the company's earnings topped Wall Street estimates, helped by a better-then-expected gross margin at its MillerCoors joint venture with SABMiller Plc.
"We come away seeing incrementally positive margin news but with added concerns about the company's share trajectory in Canada and the U.S., its two largest markets," said Stifel Nicolaus analyst Mark Swartzberg.
Molson said net income was $79.4 million, or 44 cents a share in the first quarter, down from $82.6 million, or 44 cents a share, a year earlier.
Excluding one-time items, the company earned 47 cents a share, beating analysts' average estimate of 42 cents, according to Thomson Reuters I/B/E/S.
Sales rose 0.1 percent to $691.4 million, while analysts expected $703.8 million.
Molson sold 9.9 million hectoliters of beer in the quarter, a decrease of 0.4 percent. A hectoliter is a metric unit of volume equal to 100 liters.
Last month, Molson agreed to buy East European brewer StarBev for 2.65 billion euros ($3.5 billion) to expand its footprint in developing markets.
On Tuesday, the company laid out plans for management changes once that deal is completed.
Alain Beyens, current CEO of StarBev, will leave the business at the close of the deal. Mark Hunter, now CEO of Molson's UK and Ireland businesses, will become CEO of the new business unit.
Stewart Glendinning, Molson's chief financial officer, will succeed Hunter. Gavin Hattersley was also named to succeed Glendinning as CFO. Hattersley most recently served as executive vice president and CFO for MillerCoors.
The appointments are contingent on the closing of the StarBev deal, Molson said.
Earlier on Tuesday, MillerCoors, home to brands such as Miller Lite and Coors Light, reported higher first-quarter net income, driven by price increases for its beers and warm weather, particularly in March.
Molson Coors shares fell $1.44, or 3.4 percent, to $40.60 on the New York Stock Exchange.