Official figures show that on 31 March this year, 2,025,400 people were on the register, two-fifths of the population.
The year 2011-12 also saw the highest-ever number of deceased organ donors, at 81, up by nine on the previous year.
Health secretary Nicola Sturgeon said: “It is a fantastic achievement that we have passed the two million mark. The number of Scots on the NHS Organ Donor Register is higher than ever before and higher than the UK average.
“These figures also show that we have achieved the target of a 50 per cent increase on the number of deceased donors, which the UK Organ Donation Taskforce set in 2008.
“However, we know that there is still more to be done. The tragic fact is that more than 600 people in Scotland are still waiting for a lifesaving transplant, and across the UK three people die every day because they don’t get the organ they need in time.”
New dad David Speers, who is waiting for a kidney transplant, is calling for more people to join the register.
Speers, 34, who works in the oil and gas industry in Aberdeen, was told he has chronic kidney failure in 2009. He has been on the transplant list since June last year.
He said: “I was at that point in life where I was doing all the adult things: getting married, getting a mortgage, life insurance and looking forward to starting a family.
“It all seemed routine, but fortunately the doctor doing my medical picked up signs of excessive blood and protein in my urine and referred me to a consultant who, after doing a biopsy, told me I had kidney failure. I count myself lucky it was diagnosed when it was.”