Adsorbate interactions of paramagnetic palladium(I) species in Pd(II)-exchanged K-L channel type zeolite are studied by electron spin resonance (ESR) and electron spin-echo modulation (ESEM) spectroscopies. Three different preparation methods for PdK-L by hydrogen and oxygen treatments produced different Pd(I) ESR signals. Preparation A produced one Pd(I) species which is suggested to be located at the center of hexagonal prisms of the L zeolite framework. Preparation C produced an additional Pd(I) signal which is assigned to the center of double eight rings of the zeolite framework. Preparation B produced three Pd(I) signals including a new Pd(I) signal not observed in preparations A and C. ESR and ESEM after the adsorption of various adsorbates are almost the same for PdK-L preparations A-C. Equilibration with water results in a stable Pd(I) species coordinating to one water molecule. Adsorption of benzene produces two new Pd(I) species, each coordinating to one molecule of benzene based on ESEM analysis. Adsorption of methanol or ethanol results in a new Pd(I) species along with a broad ESR signal which is attributed to the formation of small palladium clusters. ESEM shows that the new species is due to the coordination of Pd(I) to one molecule of methanol or ethanol. Upon adsorption of ethylene, two new Pd(I) species occur that show slow time-dependent changes of their ESR intensities. ESEM analysis indicates that each of the Pd(I) species coordinates to one molecule of ethylene. ESR and ESEM results indicate that equilibration with ammonia forms a new Pd(I) species interacting with one molecule of ammonia at a relatively Long distance. On the basis of its identical ESR spectrum to that for NH3 adsorption, it is suggested that one NH2 moiety of hydrazine weakly interacts with Pd(I) at a long distance as for NH3.