The present invention provides a rubber composition that achieves a well-balanced improvement in fuel economy, wet-grip performance, and abrasion resistance, and a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition, including a rubber component and silica, wherein the rubber component contains not less than 5% by mass of a conjugated diene polymer, based on 100% by mass of the rubber component, the conjugated diene polymer containing a constituent unit derived from a conjugated diene and a constituent unit represented by the following formula (I): at least one terminal of the conjugated diene polymer being modified by a compound containing a group represented by the following formula (II): and wherein the silica is contained in an amount of 5 to 150 parts by mass per 100 parts by mass of the rubber component.