UPDATE 2-3M profit falls 48 percent, cuts 2009 forecast

* Q1 EPS 74 cents vs $1.38

* EPS ex-items 81 cents; Street view 86 cents

* Cuts 2009 EPS forecast to $3.90 to $4.30

* Shares down 1.1 pct in premarket trading (Adds analyst comment, updates stock fall; changes dateline from BOSTON)

NEW YORK, April 24 - Diversified U.S. manufacturer 3M Co reported a 48 percent drop in quarterly profit and cut its full-year earnings forecast, citing falling demand as its customers reduce inventories.

3M, whose products range from Scotch tape to optical films for liquid crystal displays, said on Friday it now expects full-year earnings of $3.90 to $4.30 per share, down from a prior forecast of $4.30 to $4.70.

"That original guidance was a little aggressive anyway," said Morningstar analyst Adam Fleck.

Net income for the first quarter was $518 million, or 74 cents per share, down from $988 million, or $1.38 a share, a year earlier.

Excluding special items, profit was 81 cents per share, 5 cents below analysts' average forecast, according to Reuters Estimates.

"The weakness was pretty much where you'd expect it: electronics, automotive, construction," Fleck said.

The St. Paul, Minnesota, company is a bellwether of the U.S. economy because of its geographic reach and broad lineup of products.

3M shares fell 1.1 percent to $53.60 in premarket trading.