Relations in Captions (REC-COCO) is a new dataset that contains associations between caption tokens and bounding boxes in images. REC-COCO is based on the MS-COCO and V-COCO datasets. For each image in V-COCO, we collect their corresponding captions from MS-COCO and automatically align the concept triplet in V-COCO to the tokens in the caption. This requires finding the token for concepts such as PERSON. As a result, REC-COCO contains the captions and the tokens which correspond to each subject and object, as well as the bounding boxes for the subject and object.