Technical Abstract: Columbia root-knot nematode, Meloidogyne chitwoodi, is a major pest of potato in the Pacific Northwest of the USA and is controlled by costly soil fumigation. Potato breeding lines have been developed with resistance to the predominant race 1 (CRN-1) of M. chitwoodi. Hairy nightshade, Solanum sarrachoides, is a common weed in potato production in the Western USA and a host of CRN-1. Field and greenhouse studies were conducted with two potato lines with known CRN-1 resistance (PA95B4-67 and PA99N82-4) and a CRN-1 susceptible potato cultivar, Russet Burbank. Both resistant breeding lines grown in the absence of hairy nightshade demonstrated root resistance to CRN-1 and exhibited only minor tuber infection. However, when resistant lines were grown in the presence of hairy nightshade, some PA95B4-67 tubers were infected, whereas PA99N82-4 expressed tuber resistance. Hairy nightshade grown with potato maintained CRN-1 populations prior to potato tuber set allowing nematodes to infect developing tubers lacking resistance. PA99N82-4 grown in the presence of CRN-1 and hairy nightshade produced tubers free of CRN-1 damage, indicating both root and tuber resistance to CRN-1. Russet Burbank tubers were damaged by CRN-1 regardless of hairy nightshade presence. These results demonstrate how weed hosts of CRN-1 may negate the positive impact of growing CRN-1 resistant potatoes that lack tuber resistance and the importance of weed control on managing plant parasitic nematode populations.