ABSTRACTEcological sanitation offers both sanitation and fertilizer through recycling of nutrients. Human fertilizer provides a close to free addition of nutrients in household farming and may, therefore, decrease the downward risk of fertilizer adoption. We study an ecological sanitation investment program in southern Mali, where just over 150 beneficiaries got a urine diverting dry toilet installed. Our results suggest that the average household in our study is able to produce amounts of N, P, and K equivalent to around a fourth of its yearly expenditures on artificial fertilizers, corresponding to a yearly addition of nutrients or a yearly reduction in fertilizer expenditures to a value of about 50 €. However, the quantity and quality of N, P, and K actually retained is found to be only a fraction of this potential amount. Using propensity score matching methods, we find an increase in maize yields among beneficiary households, but no effect on the yields of other crops. Moreover, households substitute artificial fertilizer with human fertilizer at 10–15% of the average household use of artificial fertilizers. Thus, the substitution may worsen an already bad soil nutrient balance. Higher retention levels are needed for solutions to prove financially viable.