The effects of paclobutrazol (5 ppm solution) applied by immersion or through irrigation on vegetative and flowering characteristics of “Leen van der Mark”, ”Inzel” and “Rosario” tulip were determined. Plants were grown in pots inside a greenhouse in the Agricultural Experimental Station San Pedro of National Institute of Agricultural Technology (Argentina) in winter 2005. The effect of application time (0, 1, and 24 hours before transplant for immersion, and 0, 1, 11, and 21 days after transplant (dat) for irrigation) was also determined. The average temperature was 15°C. None of the treatments affected emergence time and flower length, with the exception of a slight effect for the hybrid Rosario. The effects of treatments on the length of the vegetative and flowering periods, and on the height of the plant at selling time and at the end of the flowering period depended on the hybrid. It is concluded that in order to shorten the plants of the tulip hybrids “Leen van der Mark“, “Inzel” and “Rosario”, without affecting flower characteristics and using a 5 ppm solution of paclobutrazol, it is recommended to immerse the bulbs for 24 hours, or apply it through irrigation at 21 dat.