Sisters Helen and Melissa McDonnell are missing from Killeshin Road, Carlow, since early Sunday, May 1.
Helen is 15 and described as being 1.54m (5'1") in height, of slim build and with brown hair and blue eyes.
Melissa is 14 and also 1.54m (5'1") tall and of slight build.
It is not known what either girl was wearing when they left home.
Gardaí are concerned for their safety and anyone with any information on their whereabouts should contact Carlow Garda Station on 059 9174300, the Garda Confidential Line 1 800 666 111 or any Garda station.
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