Aim. To study the Host-Guest complexation of octakis(diphenoxyphosphoryloxy)-tetramethylcalix[4]resorcinarene (PRA), 5,17-bis(N-tolyl-iminomethyl)-25,27-dipropoxycalix[4]arene (IC4A), 5,11,17,23-tetrakis(diisopropoxyphosphonyl)-25,26,27,28-tetra-propoxycalix[4]arene (PC4A) and oktakis(diethoxyphosphoryloxy)-tert-butylcalix[8]arene (PC8A)with benzaldehyde, salicylaldehyde, p-anisaldehyde, and veratraldehyde by RP HPLC and molecular modeling methods. Results and discussion. The stability constants of Host-Guest complexes (KA= 57 M-1 – 1649 M-1) strongly depend on the calixarene structure and the aromatic aldehyde nature. The enhancement of the complexing properties of calixarenes is observed in the row of PRA < IC4A < PC4A < PC8A. The volume of the calixarene molecular cavity plays the most important role in binding of aldehydes. Experimental part. The stability constants of calixarene complexes with aldehydes were determined by RP HPLC method in acetonitrile-water (80 : 20, v/v) solution. The RP HPLC analysis was performed using a LiChrosorb RP-18 column. Molecular modeling of calixarene complexes was carried out using a Hyper Chem 8.0 program. Conclusions.The Host-Guest complexation data can be used as a useful tool in design of calixarene based sensor devices for determination of the aromatic aldehydes in air or preparation of chromatographic phases for analysis of aldehydes in solutions.