18. On the Determination of Spot Parameter in Active Late-type Stars. Zboril M., Byrne P. B., Amado P. J., Gunn A. G., in Solar and Stellar Activity: Similarities and Differences, C. J. Butler & J. G. Doyle (eds), Proceedings of a Meeting held in Armagh, N. Ireland, 2-4 September 1998, ASP Conference Series Volume 158, p.178. Compressed Postscript (47 kbytes) Compressed PDF (302 kbytes) ABSTRACT. Photometric and spectroscopic variability of active late-type stars are frequently interpreted as evidence for magnetic activity analogous to solar activity. In particular cool, dark spots with enhanced photospheric magnetic fields are invoked to explain both photometric and spectroscopic variability. In one of the diagnostic methods, the features such as TiO and VO in spectra were suggested to detect spots in stellar atmospheres of cool stars. In this contribution we discuss the TiO band technique and its limits using our own spectroscopic material.