Figures obtained under Freedom of Information laws show 788 elective procedures were cancelled in Scotland between December 17 and January 24, with 446 in NHSGGC.
The operations were cancelled due to increased pressures on hospitals, including the norovirus and other winter illnesses.
The Scotland Patients' Association (SPA) said the figures were "horrendous" and that procedures should be carried out at weekends during busy periods.
Margaret Watt, SPA chairwoman, said: "Why, when they know these pressures come every year, do they not make contingency plans?
"This has a big impact on patients. It doesn't just knock back the patients concerned but also those waiting for their operations to be scheduled."
The figures show Glasgow is by far the worst offender, then NHS Tayside with 90, NHS Highland with 82 and NHS Fife with 71.
A spokeswoman for NHSGGC said: "While we have done everything we can to avoid having to postpone non-urgent planned inpatient procedures we have had to reschedule 446."