This multicenter prospective potential living kidney donor cohort study investigated which sociodemographic and other factors predict progression to living kidney donation or donor withdrawal as little is known on this topic. Therefore, we examined data on individuals undergoing living donor assessment at seven hospitals in the United Kingdom. Multivariable logistic regression was used to explore the relationships between donor and recipient characteristics and likelihood of kidney donation. A total of 805 individuals presented for directed donation to 498 intended recipients, of which 112 received a transplant from a living donor. Potential donors were less likely to donate if their intended recipient was female rather than male with an odds ratio of 0.60, a friend rather than relative 0.18, or had renal failure due to a systemic disease rather than another cause 0.41. The most socioeconomically deprived quintile was less likely to donate than the least 0.49, but the trend with deprivation was consistent with chance. Higher body mass index was associated with a lower likelihood of donation (odds ratio per each kg/m increase, 0.92). Younger potential donors (odds ratio per each year increase 0.97), those of nonwhite ethnicity 2.98, and friend donors 2.43 were more likely to withdraw from work-up. This is the first study in the United Kingdom of potential living kidney donors to describe predictors of non-donation. Qualitative work with individuals who withdraw might identify possible ways of supporting those who wish to donate but experience difficulties doing so.