United Rentals Inc. said late Tuesday that its first-quarter profit rose to $38 million, or 34 cents a share, from $30 million, or 28 cents a share, in the year-ago period.

The company posted total revenues of $772 million for the fiscal quarter, compared to $838 million in the comparable quarter a year earlier. Analysts surveyed by FactSet Research estimated a quarterly profit of 34 cents a share on revenue of $803.5 million.

The company also reduced its earnings guidance for 2008 to the range of $2.65 per share to $2.85 per share from the earlier outlook in the range of $2.80 per share to $3.00 per share. Analysts estimate $2.72 a share on revenue of $3.55 billion.

United Rentals slashed its 2008 guidance to the range of $1.15 billion to $1.19 billion from the earlier outlook ranging from $1.17 billion to $1.21 billion. The company said it currently expects full year free cash flow after total capital expenditures to be in the range of $400 million to $450 million.