The number of unattributed paintings by Amedeo Modigliani is estimated, using the method of multiple systems estimation (MSE). Most major artists’ works are listed in one catalogue raisonné, but there are five catalogues purporting to list Modigliani paintings. These can be treated as list sources from which MSE can be applied. We obtain estimates by following the classical MSE approach using log-linear models, and compare these with estimates obtained via a Bayesian non-parametric latent class approach. We also consider the impact of fake paintings through sensitivity analyses. Our estimates point to there being around 20–120 unattributed Modigliani paintings.