Most countries prohibit compensation for plasma donations, and Canada continues to consider a ban. Foremost among reasons for prohibition is the worry that compensated plasma will decrease uncompensated blood donations. Using difference-in-differences analysis of data containing plasma and blood donations in Canada spanning a period in which the country’s only three paid-plasma centers began operating, we examine whether the introduction of paid-plasma decreased blood donations overall and among young donors. We find no evidence of a decrease but rather a small increase. We replicate this finding in U.S. cities that experienced the introduction of paid-plasma over a similar time period.