Objective Bayesian Distribution Fitting R package fitdistrBayes version 0.5.0 Fits common univariate distributions using registered objective Bayesian priors, including Jeffreys, reference, and maximal data information priors, and supports user-defined distributions and priors through an extensible model specification. Model-specific posterior propriety and moment conditions are checked before computation when registered or supplied. Exact simulation, marginalization, slice sampling, adaptive Metropolis, and user-supplied posterior samplers share a common interface for summaries, diagnostics, prediction, and pointwise log-likelihood evaluation. A separate interface fits independently right-censored observations using the registered complete-data priors, observed-data likelihood sampling or data augmentation, with sufficient posterior-propriety checks. Optional post-processing provides WAIC, PSIS-LOO, and DIC for observed-data likelihoods. The reference-prior framework follows Bernardo (1979) <doi:10.1111/j.2517-6161.1979.tb01066.x>. Software Depends: R (>= 4.1.0) Suggests: posterior, loo (>= 2.7.0) Pedro Luiz Ramos <pedro.ramos@uc.cl> Comprehensive R Archive Network (CRAN) Pedro Luiz Ramos [aut, cre, cph] GPL-3 2026-09-21 application/tgz https://CRAN.R-project.org/package=fitdistrBayes doi:10.32614/CRAN.package.fitdistrBayes en-US