Context : Until now , most members of the Ursa Major ( UMa ) group of stars have been identified by means of kinematic criteria .
However , in many cases kinematic criteria alone are insufficient to ascertain , whether an individual star is really a member of this group .
Since photometric criteria are ineffective in the case of cool dwarf members , one must use spectroscopic criteria .
Nevertheless , resulting membership criteria are inconclusive .

Aims : We reanalyse spectroscopic properties of cool UMa group dwarfs .
In particular , we study the distribution of iron abundance , the strength of the Li I absorption at 6708 \mathrm { \AA } and the Li abundance , and the infilling of the core of the H \alpha line .

Methods : Twenty-five cool and northern bona-fide members are carefully selected from the literature .
Homogeneously measured stellar parameters and iron abundances are given for all Sun-like stars selected , based on spectra of high resolution and high signal-to-noise ratio .
In addition , we measure the Li equivalent width and abundance as well as the relative intensity of the H \alpha core and the corresponding chromospheric flux .

Results : The studied stars infer an average Ursa Major group iron abundance of -0.03 \pm 0.05 dex , which is higher by about 0.06 dex than determined elsewhere .
The Li abundance derived of Ursa Major group dwarf stars is higher than in the Hyades at effective temperatures cooler than the Sun , but lower than in the younger Pleiades , a result which is independent of the exact value of the effective temperature adopted .
The Sun-like and cooler dwarfs also display chromospheric infilling of the H \alpha core .
We present spectroscopic criteria that may be used to exclude non-members .

Conclusions :