Basis of Presentation

9 Months Ended

Sep. 30, 2011

Basis of Presentation

Basis of Presentation

1. Basis of Presentation

The unaudited interim condensed consolidated financial statements for the three and nine month periods ended September 30, 2011 and 2010 have been prepared on the same basis as the audited financial statements for the year ended December 31, 2010. The financial statements include all normal recurring adjustments, which we consider necessary for a fair presentation of the financial position at such dates and the operating results and cash flows for those periods. Results for the interim periods are not necessarily indicative of the results for the entire year. For more complete financial information, these financial statements, and notes thereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2010 included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”).

The condensed consolidated financial statements include the accounts of Isis Pharmaceuticals, Inc. (“we”, “us” or “our”) and our wholly owned subsidiaries, Isis USA Ltd. and Symphony GenIsis, Inc.  We use the equity method of accounting to account for our investment in Regulus Therapeutics Inc.