Karstification is a phenomenon that is more common in limestone and gypsum than in other rocks. Despite their equal geo-logical conditions such as tectonics and hydrology, karstification in limestone and gypsum is different in the Ramhormoz area in Zagros folded zone in the southwest of Iran. This study aims to evaluate the lithological, physical, and mechanical properties of gypsum and limestone from Gachsaran and Asmari formations in the Ramhormoz area as well as their rela-tionship with karstification features. This investigation involves two main parts: a morphological study and laboratory tests. First, morphological features of karsts were measured in gypsum and limestone. Then lithological, physical, and mechanical properties of the two were measured using laboratory tests such as SEM and XRD analyses, a calcimeter test, dry density, saturated density, porosity, solubility, durability, Uniaxial Compressive Strength (UCS), and the Brazilian tensile tests. In the next step, the relationship between laboratory properties and karstification phenomena in these types of rocks was obtained. In this study, limestones were divided into four types based on calcite content, and gypsums were divided into two types based on texture: alabaster gypsum and porphyritic gypsum. Karst morphology studies show a higher frequency and larger dimensions of caves and karrens in limestone types 1 and 2, and collapse and cap rock sinkholes in porphyritic gypsum. The results of laboratory tests show that, compared to gypsum, limestone has higher compressive strength and slake durability and low dissolution potential. Because of their high strength and durability, karst features such as cave and karren are more stable in limestone compared to gypsum which has low strength and durability and high dissolution and is also unstable. According to this research, the karst in limestone is stable while in gypsum it is unstable

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