McBreen has published several volumes of poetry, including The Wind Beyond the Wall (1990), A Walled Garden in Moylough (1995), Winter in the Eye: New and Selected Poems (2003) and Heather Island (2009). She is more widely known as the editor of two anthologies. The White Page: Twentieth-Century Irish Women Poets, published in 1999, garnered praise for drawing attention to overlooked female poets. Her 2009 anthology The Watchful Heart: A New Generation of Irish Poets - Poems and Essays, highlights lesser-known younger Irish poets and has received positive reviews for its selections.