UPDATE 3-McGraw-Hill net down 22 pct, FY revenue view cut

* EPS 20 cents vs 25 cents; revenue down 6 percent

* Grade school textbook sales decline

* Shares down 3.3 percent in afternoon trading (Adds analyst comment, updated share fall, adds byline)

By Jonathan Stempel

NEW YORK, April 28 (Reuters) - McGraw-Hill Cos Inc (MHP.N: Quote, Profile, Research) said quarterly profit fell 22 percent amid lower demand for elementary and high-school textbooks and for credit ratings on mortgages and other complex debt.

The New York-based company also cut its full-year revenue forecast on Tuesday, but left its earnings forecast unchanged as it keeps a lid on costs.

First-quarter net income attributable to shareholders fell to $63 million, or 20 cents per share, from $81.1 million, or 25 cents, a year earlier.

Analysts on average expected 18 cents per share, according to Reuters Estimates. Revenue fell 6 percent to $1.15 billion, roughly matching estimates. Expenses were down 4 percent.

"The challenging economy, a seasonally slow start in the elementary-high school business and continued weakness in advertising and the structured finance market were important factors in our first-quarter decline," Chief Executive Harold "Terry" McGraw said in a statement. "Cost containment will be a priority for us all year."