  We present the main results of broad band (0.1-10 keV) BeppoSAX observations
of a selected sample of Narrow Line Seyfert 1 galaxies (NLS1s). We have
performed a spectroscopic analysis of LECS and MECS data to test their average
spectral properties, and timing analysis to study their amplitude variability.
The steep average spectral indices and the high amplitude time variability are
in agreement with a scenario where NLS1s, with respect to the Broad Line
Seyfert 1 (BLS1s) host a smaller black hole mass surrounded by hotter accretion
disc.
