In the commercial production of guava seedlings (Psidium guajava L.) the quality of the cuttings, homogeneity, high percentage of rooting are the factors important to be analyzed. Therefore, as the Século XXI cultivar is recent, it is necessary to do more studies regarding the behavior of this guava to the factors that aid in the rhizogenic process. The objective of this work was to verify the concentrations of indolebutyric acid (IBA) that provide the best rooting of cuttings herbaceous and semihardwood, as well as to verify the best kind of cuttings used for vegetative propagation the guava cuttings cultivar ‘Século XXI’. The experimental design was completely randomized in a 5 x 2 + 1 factorial design, beginning with five concentrations of IBA (0, 1000, 1500, 2000 and 2500 mg L-1), two kinds of cuttings (herbaceous and semihardwood) and one control treatment (immersed in distilled water for 12 hours), with four replications and 10 cuttings per plot. In relation of the variables: the percentage of cuttings live without roots, callus, number of roots and dry weight of shoots did not present significant interaction among treatments, not adjusting to any regression model. Therefore, concluding that the herbaceous cutting is the most indicated for the propagation of guava seedlings of ‘Século XXI’; The concentration of 2500 mg L-1 of IBA promotes a higher percentage of rooted semihardwood cuttings without leaf; The hormone solution diluted with alcohol 50% (v/v) resulted in toxicity for herbaceous and semihardwood cuttings cv. Século XXI.