We study from first principles the magnetism in graphene induced by single carbon atom defects. For two types of defects considered in our study, the hydrogen chemisorption defect and the vacancy defect, the magnetism due to the defect-induced extended states has been observed. Calculated magnetic moments are equal to 1 μB per hydrogen chemisorption defect and ∼1.5 μB per vacancy defect. The magnetic ordering is either ferromagnetic or antiferromagnetic, depending on whether the defects correspond to the same or to different hexagonal sublattices of the graphene lattice, respectively.