As already reported, the FINAPRES device is able to monitor blood pressure (BP) variations in a beat-to-beat fashion both in resting conditions and during different laboratory manoevres, providing BP values close to those simultaneously recorded by an intra-arterial line. Whether this applies not only to the assessment of BP mean values but also to the evaluation of specific components of BP variability, as determined by spectral analysis, is not known however. We have addressed this issue by assessing the spectral characteristics of BP and heart rate (pulse interval, PI) of continuous finger and intra-arterial BP recordings simultaneously obtained in 14 untreated essential hypertensive patients. Spectral powers were computed by Fast Fourier Transform (FFT) over three frequency bands defined as Low Frequency (LF, 0.025-0.07 Hz), Mid Frequency (MF, 0.07-0.14 Hz) and High Frequency (HF, 0.14-0.35 Hz) band. All powers of mean arterial pressure (MAP) and diastolic (D) BP estimated from analysis of finger BP tracings were superimposable to those obtained by analysing intra-arterial recordings. This was the case also for HF powers of systolic (S) BP, while LF and MF powers of intra-arterial SBP were over-estimated by the analysis of finger BP tracings (+ 13.7± 4.4 mmHg²; p<0.01 and +2.3±0.9 mmHg²; p<0.05). Thus beat-to-beat finger BP recording seems to represent an acceptable substitute of invasive recording also in the analysis of BP and PI spectral components. Some caution is needed, however, in interpreting LF and MF powers of SBP which are overestimated by the analysis of finger BP tracings.