This study was carried out to determine the optimum irrigation water amount and interval for carnation plants (Dianthus caryophyllus L.) using the pan evaporation method. The values of class A pan, located inside the greenhouse, were used to determine the irrigation water amount. Irrigation treatments consisted of three irrigation intervals (I1: 1-, 12: 2-, and I3: 3-day) and five crop-pan coefficients (k(cp)1: 0.25, k(cp)2: 0.50, k(cp)3: 0.75, k(cp)4: 1.00, and k(cp)5: 1.25). Irrigation water amounts applied to the experimental treatments ranged from 218 to 786 mm; seasonal evapotranspiration ranged from 219 to 601 mm and the yield acquired from the treatments ranged from 10 to 89.82 stems/m(2). The highest yield was obtained from I1k(cp)4 (89.56 stems/m(2)) followed by I1k(cp)5 (82.89 stems/m(2)) and I1k(cp)3 (82.22 stems/m(2)). The seasonal yield response factor (k(y)) was calculated to be 0.73, 1.00, and 1.42 in I1, I2, and I3, respectively. Significant relationships were obtained between yield and irrigation water (R-2 = 0.998) and evapotranspiration (R-2 = 0.993) in the I1 treatments, in which the highest yield was found. In carnation cultivation under greenhouse conditions, it was proposed to apply irrigation water with 1-day intervals under a crop-pan coefficient of k(cp)4.