The overall pitch of a recorded speech sample could be subjected to pitch shift techniques available with the advancement in digital technology. Effect on speech characteristics due to time domain pitch shift technique have been undertaken using time warping. Study on the effect of frequency domain pitch shift by preserving tempo has been conducted with the speech exemplars of 15 speakers at a stretch ratio of 90, 95, 105 and 110 as compared to the original speech exemplar. Effect due to frequency domain pitch shift on F1, F2, F3, nasal formant frequencies, duration of word segment and mean period are analyzed with respect to the overall shift in the mean F0. The change in pitch due to stretching is found independent of the position of F1, F2 and F3. However, the change in the values of F1, F2, F3 and mean period for a speaker is linear. Note: The paper was presented at XVI All India Forensic Science Conference 2004, Hyderabad, India and appeared in the Proceedings.