An increasing number of patients and families are utilizing online crowdfunding to support their medical expenses related to organ transplantation. The factors influencing the success of crowdfunding campaigns are poorly understood. Crowdfunding campaigns were abstracted from a popular crowdfunding web site. Campaigns were included if they were actively accepting donations to fund medical expenses related to transplantation of selected organs. The primary outcome measure was total amount raised among successful campaigns receiving at least one donation. Bivariate and multivariate analyses were performed on various campaign characteristics. A total of 850 campaigns were analyzed. Kidney transplant campaigns were most common (40.5%), followed by liver (33.3%), lung (12.2%), heart (11.3%), and multiorgan (2.7%). 69.1% of campaigns received any donation, and among these, the mean amount raised was $3664 (median $1175). The following factors were significantly associated with amount raised: more positive emotional sentiment in the campaign description (+2.6% per AFINN unit, P < .001), longer campaign description length (+2.4% per 100 characters, P = .001), higher goal amount (+0.6% per $1000 of goal amount, P = .004), and third-person description perspective (+131% vs first person, P < .001). Physicians will likely encounter medical crowdfunding with increasing frequency as it continues to grow in popularity among their patients.