The probe, ordered after two laptops containing thousands of bank details were stolen in May, found that hundreds of laptops and PCs were unaccounted for and almost another 100 items were missing.
The laptops stolen from a City Chambers' office contained about 17,000 bank details – of major businesses and individuals – with neither system category encrypted.
The report shows that "no part of the council's desktop PC estate is encrypted".
In all, 256 unsecured laptops and 487 desktop PCs, also expected to be unencrypted, are unaccounted for.
The report, by the council's chief inspector, states: "These losses referred to indicate that theft has occurred on a significant scale over a number of years from a 'secure area', and it would also appear to show that these thefts have been well-organised and systematic."
May's theft, which is expected to lead to a six-figure fine for the council from the UK's Information Commissioner, led to an audit of all the council's IT hardware, which is run by public-private partnership Access.
As well as the near 750 devices unaccounted for, the report says "a further nine incidents of theft involving 37 pieces of equipment have been reported" across the city. These include 28 laptops, three Blackberries and two desktop PCs.
"Where appropriate, these losses were reported to Strathclyde Police", the report states. Access has also reported the loss of 53 laptops from its city-centre premises.
SNP group leader Graeme Hendry said: "This report strongly suggests Glasgow's management of IT systems has been chaotic at best. To lose two laptops is worrying but nearly 750 is beyond belief."
A council spokesman said the report shows "that for a number of years the council family has been poor at keeping accurate records of its IT equipment. We're now dealing with that situation".