One of the proposed constitutional amendments would prohibit the state from establishing a health insurance exchange.
The other requires voters to present photo identification at the polls.
Each needs more than 101,000 signatures by the end of the day to be certified for the November ballot, including more than 25,000 from each of four congressional districts.
If either wins in the fall, voters would have to approve it again in 2016 to become law.
Backers of legalizing marijuana in Nevada have another five months to gather signatures in their petition drive aimed at bringing the matter before the Legislature next year.