It looks like the smallest unanimous vote in the 113&#x2F;114th congresses was 353.<p><a href="http:&#x2F;&#x2F;clerk.house.gov&#x2F;evs&#x2F;2013&#x2F;roll631.xml" rel="nofollow">http:&#x2F;&#x2F;clerk.house.gov&#x2F;evs&#x2F;2013&#x2F;roll631.xml</a><p>For the Senate, 83.<p><a href="http:&#x2F;&#x2F;www.senate.gov&#x2F;legislative&#x2F;LIS&#x2F;roll_call_votes&#x2F;vote1141&#x2F;vote_114_1_00300.xml" rel="nofollow">http:&#x2F;&#x2F;www.senate.gov&#x2F;legislative&#x2F;LIS&#x2F;roll_call_votes&#x2F;vote11...</a>