The structure and thermodynamic characteristics of random aliphatic copolyamide based on caprolactam and hexamethylenediamine adipate and sebacate are investigated by roentgenography, polarization microscopy, light scattering, differential thermal analysis, differential scanning calorimetry, and thermomechanical analysis. The phase diagrams of the copolyamide solutions in ethanol and N-methyl pyrrolidone are obtained. Gel transition in such systems is studied by calorimetry. A comparison of the structure and characteristics of gels formed of solution and block copolyamide is performed using polarization microscopy, differential thermal analysis, and differential scanning calorimetry. The copolyamide is found to have extremely low crystallinity, which nevertheless substantially governs its characteristics. The experimental results are discussed in terms of microcrystallites formed due to interchain hydrogen bonding present in the structure of copolyamide.