  We studied the correlations between spin frequencies and kilohertz
quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries.
The updated data of kHz QPOs and spin frequencies are statistically analyzed.
We found that when two simultaneous kHz QPOs are present in the power spectrum,
the minimum frequency of upper kHz QPO is at least 1.3 times larger than the
spin frequency, i.e. \nu_{s}<\nu_{2min}/1.3. We also found that the average kHz
QPO peak separation in 6 Atoll sources anti-correlates with the spin frequency
in the form \lan\dn\ran = -(0.19\pm0.05)\ns+(389.40\pm21.67)Hz. If we shifted
this correlation in the direction of the peak separation by a factor of 1.5,
this correlation matches the data points of the two accretion powered
millisecond X-ray pulsars, SAX J1808.4-3658 and XTE J1807-294.
