A recent review suggests that the commonly cited value of 1.45×1010cm−3for the silicon intrinsic carrier concentration at 300 K is inconsistent with the best experimental and theoretical results. An alternative value of 1.08×1010cm−3was suggested. A new experimental measurement of 1.01×1010cm−3is reported with an estimated one standard deviation uncertainty of only 3%. This appears to be the most accurate experimental determination of this parameter at any temperature.