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Abstract. Heat stress affects animal health, welfare, and productivity. Animal sound analysis has shown useful as an early warning tool of heat stress in some animal species, but it has not yet been studied in turkeys. The objectives of this study were to develop method for turkey sound analysis and determine whether heat stress can induce specific turkey vocalizations. Forty-eight turkeys were bred in 8 isolated rooms under laboratory conditions for 8 weeks and randomly allotted to heat stress (HS) rooms and control (CON) rooms. Turkeys in the HS rooms were exposed to high room temperature three times during the study. Temperatures in the HS rooms were increased from 21 to 34 °C from 9:00 a.m. to 11:20 a.m., kept at 34 °C for 2 h before lowing back to 21 °C during the tests days. The temperature in the CON rooms was maintained at 21 °C. Turkey vocalizations were continuously recorded. The recorded sounds were analyzed using MATLAB. Fast Fourier Transform (FFT) and Mel-Frequency Cepstral Coefficients (MFCC) were used to process the sound signals in the frequency domain and time-frequency domain, respectively. Support vector machine (SVM) was used as the classifier for sound signal recognition. Zero-crossing rate (ZCR) in the time domain, main frequency (MF) in the frequency domain and 3^rd dimension MFCC (3D-MFCC) in the time-frequency domain were found the three best sound features. The accuracy of classification was 88.75% based on SVM and the three selected features. The numbers of turkey vocalizations under HS were 43% more than under CON conditions. Turkeys responded to heat stress within 30 min by producing more vocalizations. The results demonstrated the possibility of using turkey vocal sound monitoring and analysis as an early warning tool for heat stress detection.