BV observations of W UMa-type binaries - CK Boo, BI CVn, and AH VIR Photoelectric BV observations of W UMa-type binaries CK Boo, BI CVn, andAH Vir are presented, and light curve variations and shifts of minimaare discussed in the context of stellar activity and mass transfer. TheO-C increments in three systems were found to be 0.08, 0.80, and 0.60 sper revolution, respectively. The new ephemeris for the futureobservations were also found.