Ian Gollop, the county councillor for St Dogmaels and Nevern, has stepped down due to ill health.
Mr Gollop was elected as councillor in September last year.
"It is after much thought, consideration and on medical advice that I regretfully submit my resignation," he said.
"I have greatly enjoyed being a county councillor and have met many people and made many new friends, which only confirms my deep conviction of the strength and goodness of our community we are indeed fortunate to live in."
Mr Gollop will continue his role as a community councillor in St Dogmaels.
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