Sigma-Aldrich's reported sales for the first quarter of 2010 were $572 million, an increase of 10.2% from the first quarter of 2009. Excluding a 5.8% benefit from favorable currency rates, first quarter organic sales growth was 4.4% driven largely by unit volume growth. Sales for the company's research business grew 8.8% on a reported basis and 2.8% organically for the first quarter of 2010. Sales for SAFC continued the momentum that began in the second half of 2009, with first quarter reported growth of 14.3% and organic growth of 9.0% as sales of high potency active pharmaceutical ingredients and hitech products reflected strong demand from those markets.
The operating income margin in the first quarter of 2010 of 25.7% of sales reflects a 160 basis point improvement from 2009's first quarter due to continued benefits from higher volumes, the company's supply chain initiative, favorable product mix and effective management of S,G&A costs. These items were partially offset by $6 million of restructuring costs to consolidate certain SAFC manufacturing facilities and from a small workforce realignment. These previously announced restructuring actions are in line with the company's efforts to improve operating efficiencies and lower the fixed cost structure as part of its longer term program to improve operating margins to a 26% to 27% range over the next five years. Supply chain process improvements provided over $4 million of the Q1 2010 pretax enhancement.
Free cash flow for the first quarter of 2010 was $133 million, an increase of $47 million compared to the same period in 2009. Higher net income, a continued focus on inventory management and a lower level of capital expenditures were the primary contributors to this increase.
Other highlights from global sales growth initiatives and profit enhancement activities include: