On April 20, 2020, New Jersey (NJ) implemented a comprehensive ban on the sale of flavored e-cigarettes. This study compares sales of e-cigarettes, cigarettes, and cigars before and after the law. Data were biweekly retailer scanner sales in NJ convenience stores for e-cigarettes, cigarettes, and cigars between August 2019 and December 2020. We used Joinpoint regression to assess sales trends for cigarettes (non-menthol, menthol), cigars (unflavored, flavored), and e-cigarettes (unflavored, fruit/sweet/concept flavor, menthol flavor) in the 36 weeks before and 36 weeks after a statewide ban on flavored e-cigarettes. Flavored e-cigarette sales, not including menthol, significantly decreased over the study period while menthol e-cigarette sales significantly increased until the e-cigarette flavor ban took effect, after which these sales rapidly declined through May 2020, then slowed. Unflavored e-cigarette sales declined through September 2019, then grew modestly until the flavored e-cigarette ban, after which sales significantly increased. Flavored cigar sales increased between March and May 2020, then declined; non-flavored cigar sales increased between mid-February and early July 2020, then declined. Cigarette sales were decreasing before the flavored e-cigarette ban but after, significantly increased until June 2020. Overall, there was no significant trend in the average biweekly percent change for cigarette sales. Flavored e-cigarette sales were declining prior to the ban but the pace of the decline accelerated following federal and state restrictions on flavored e-cigarette sales, then slowed by the second half of 2020, with a brief period of increased cigarette and cigar sales immediately following the ban. New Jersey's 2020 statewide e-cigarette flavor ban offered the opportunity to observe how sales of e-cigarette, cigarette, and cigar products shifted after the change. The effect of the state law, at least in the short-term, was decreased sales of flavored e-cigarettes and increased sales of unflavored e-cigarettes. Research on long term policy effects is needed.