This work indicates the device properties of polycrystalline p-AgGaInTe2 (AGIT) thin films deposited on bare and ITO-coated glass substrates with thermal evaporation technique. Device characteristics of n-CdS/p-AGIT heterostructure have been analyzed in terms of current-voltage (I-V) for different temperatures and capacitance-voltage (C-V) measurements for different frequencies, respectively. The series and shunt resistances were determined from the analysis of parasitic resistance for high forward and reverse bias voltages, respectively. The ideality factors were evaluated from I-V variation at each sample temperature as lying in between 2.51 and 3.25. The barrier height was around 0.79 eV at room temperature. For low bias region, the variation in the diode parameters due to the sample temperature exhibited the thermionic emission with T-0 anomaly, whereas space-charge-limited current analysis was also found to be pre-dominant carrier transport mechanism for this heterostructure. From C-V measurements, the obtained built-in potential and series resistances were found to be in good agreement with I-V results.