There are provided a method of forming a fine pattern employing self-aligned double patterning. The method includes providing a substrate. First mask patterns are formed on the substrate. A reactive layer is formed on the substrate having the first mask patterns. The reactive layer adjacent to the first mask patterns is reacted using a chemical attachment process, thereby forming sacrificial layers along outer walls of the first mask patterns. The reactive layer that is not reacted is removed to expose the sacrificial layers. Second mask patterns are formed between the sacrificial layers adjacent to sidewalls of the first mask patterns facing each other. The sacrificial layers are removed to expose the first and second mask patterns and the substrate exposed between the first and second mask patterns. The substrate is etched using the first and second mask patterns as an etching mask.