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Hydrogen sulfide (H 2 S) is an endogenous gasotransmitter with potential therapeutic value for treating a range of disorders, such as ischemia-reperfusion injury resulting from a myocardial infarction or stroke. However, the medicinal delivery of H 2 S is hindered by its corrosive and toxic nature. In addition, small molecule H 2 S donors often generate other reactive and sulfur-containing species upon H 2 S release, leading to unwanted side effects. Here, we demonstrate that H 2 S release from biocompatible porous solids, namely metal–organic frameworks (MOFs), is a promising alternative strategy for H 2 S delivery under physiologically relevant conditions. In particular, through gas adsorption measurements and density functional theory calculations we establish that H 2 S binds strongly and reversibly within the tetrahedral pockets of the fumaric acid-derived framework MOF-801 and the mesaconic acid-derived framework Zr-mes, as well as the new itaconic acid-derived framework CORN-MOF-2. These features make all three frameworks among the best materials identified to date for the capture, storage, and delivery of H 2 S. In addition, these frameworks are non-toxic to HeLa cells and capable of releasing H 2 S under aqueous conditions, as confirmed by fluorescence assays. Last, a cellular ischemia-reperfusion injury model using H9c2 rat cardiomyoblast cells corroborates that H 2 S-loaded MOF-801 is capable of mitigating hypoxia-reoxygenation injury, likely due to the release of H 2 S. Overall, our findings suggest that H 2 S-loaded MOFs represent a new family of easily-handled solid sources of H 2 S that merit further investigation as therapeutic agents. In addition, our findings add Zr-mes and CORN-MOF-2 to the growing lexicon of biocompatible MOFs suitable for drug delivery.