Department of Eletrical Engineering Universidade Estadual de Campinas Campinas, SP, Brazil ABSTRACT This paper presents some preliminary methods to apply the TimeFrequency Interpolation technique TFI  to concatenative text-to-speech synthesis. The TFI technique described here is a pitch-synchronous time-frequency approach of the well known Prototype-Waveform Interpolation technique PWI . The basic concepts of representing the speech signal in the Time-Frequency Domain as well as techniques to perform Time-Scale and PitchScale modifications are described. Using the flexibility of TFI technique to perform spectral smothing, a method was developed to minimize the spectral mismatch at the boundaries of the Synthesis-Units SUs. The proposed system was evaluated using SUs (Diphones) and prosodic modifications generated by the Festival system . An informal subjective test was performed, between the proposed TFI system and the standard TD-PSOLA system, highligthing the superior quality of the proposed system in comparasion with TD-PSOLA.