Despite a 10-percentage point drop since 2009, 69% of patients remain satisfied with their GP service - well ahead of the overall NHS satisfaction rate of 60%, according to the British Social Attitudes survey published by the King's Fund.
The findings come just a month after the national GP patient survey showed that 85% of patients rate the overall experience of their practice as 'good'.
GP leaders said the poll reflected hard work by practices in the face of a growing crisis.
Waiting too long for GP or hospital appointments was the most common reason patients gave for dissatisfaction with NHS services, with 55% citing this as a factor.
Meanwhile, a GPonline investigation earlier this year revealed that patient satisfaction rates were closely linked to funding - with practices receiving the highest levels of funding per weighted patient likely to score higher on satisfaction.
RCGP chairwoman Dr Maureen Baker called for more investment in GP services, and said: 'It is testament to the hard work and dedication of GPs and their teams across the country that at a time of such intense resource and workforce pressures, patient satisfaction with our service is the highest in the NHS.
'The demands on general practice are currently enormous, and with our ageing population, and increase in patients living with multiple, long-term conditions, this is only set to grow.
'This year we will make in excess of 370m patient consultations this year – 60m more than we did five years ago – but despite this increase in workload our workforce has remained relatively stagnant, and over the last 10 years funding for our service has declined.
'This relentless pressure is a threat to our own health and our patients' safety – and this report today indicates that it is gradually wearing down the satisfaction our patients have in us.'
NHS Alliance co-chair Dr Mark Spencer said: 'Although it’s disappointing that public satisfaction with the NHS has fallen, it is by no means a surprise. There are two prime reasons for this. Firstly, it is harder for people to make an appointment at their GP practice.
'The severe shortage of GPs has been well documented, and this is coupled with practices being expected to take on more and more care, as services move from hospitals to the community. Secondly, ever increasing patient expectations are being fuelled by politicians making promises that the dwindling NHS workforce cannot hope to deliver.'
Dr Spencer called for 'proper investment in all community and social care providers, including general practice, community pharmacy, and care for the elderly among others' to deliver sustainable out-of-hospital care.