  Earlier observations of NGC 1808 in various wavebands (X-ray, optical,
near-infrared, radio) provided evidence for the existence of either a starburst
or a Seyfert 2 nucleus. We here present the results of multiwavelength
XMM-Newton and Chandra observations, which directly prove the co-existence of
thermal diffuse plasma and non-nuclear unresolved point-like sources associated
with the starburst activity, along with a Low Luminosity Active Galactic
Nucleus (LLAGN) or an Ultra Luminous X-ray source (ULX). The broad bandwidth of
XMM-Newton allows us to show that the unresolved nuclear source in NGC 1808
dominates the hard X-ray spectrum, while the emission in the soft regime, below
1 keV, is dominated by a thermal component associated to an extended starburst.
Both EPIC and RGS data provide reliable detections of a number of emission
lines from heavy elements, with abundances ranging from roughly 0.7 to 2.2
Z_sol for different elements. However, no 6.4 keV Fe K-alpha fluorescence line
emission was detected. The analysis of the nuclear region of NGC 1808 allows us
to detect and disentangle the contribution of an unresolved nuclear X-ray
source and the starburst region, but the exact nature of the nucleus remains
unknown. The observed luminosity of NGC 1808 is L(2-10 keV)=(1.61+/-0.06)E+40
erg/s. A comparison of our OM 212 nm image with a CTIO 4-m telescope H-alpha
frame shows a good general correspondence between the emission from massive
stars and warm ionized gas, with minor deviations near the ends of the bar in
NGC 1808. An aditional, very soft thermal spectral component with kT~0.1 keV
has been discovered in the XMM-Newton spectral analysis, which most likely
originates from the halo of NGC 1808.
