Praseodymium, lanthanum indates solid solutions Pr[1–x]La[x]InO[3] were synthesized by ceramic method for the first time. It was found that in PrInO[3] – LaInO[3] binary system there was a continuous range of praseodymium-lanthanum indates solid solutions Pr[1–x]La[x]InO[3] with the structure of orthorhombically distorted perovskite. Thermal elongation of synthesized samples was investigated in 400–1,120 K temperature range. Сomplex thermal analysis of the samples synthesized was carried out up to 1,273 K. Temperature dependences of relative elongation had no anomalies due to the phase transitions and using these dependences average linear coefficients of thermal elongation were calculated by leastsquares technique. On the differential scanning calorimetry (DSC) curves for all the samples investigated no thermal effects were observed.