Purpose: This study evaluates the effectiveness of two different programs of voice-treatment on a heterogeneous group of dysphonic speakers and the stability of therapeutic progress for longterm follow-up post-treatment period, using a limited multidimensional protocol of evaluation. Method: Forty-two participants with voice disorders were randomly assigned to one of two groups. Participants in group 1 received voice-therapy and participants in group 2 received a vocal-hygiene program. Vocal function was assessed before and after treatment. Results: MANOVA analysis Pillai's trace test shows significant pre-post immediate differences between treatments in favor of direct-intervention. Repeated-measures ANOVAs display significant within subjects main effect for follow-up period in the 8 measures considered. Interaction effects of groupxtime are also found in five out of the eight continuous variables analyzed (3 aerodynamics-acoustic and 2 self-rating), indicating differences between both treatments. Qualitative dimensions (perceptual, laryngoscopic and spectrographic assessments) also support voice-therapy superiority. Conclusions: Results of this study suggest superiority of a voice-therapy (direct treatment) approach over a vocal-hygiene program (indirect treatment). This advantage is on the majority of the 8 continuous variables analyzed (aerodynamics, acoustic, and self-rating), including qualitative perceptual, laryngoscopic and spectrographic voice-dimensions. The stability of changes is extended during a post-treatment follow-up period. Learning outcomes: (1) The reader should distinguish the advantage using one type of treatment or another in clinical contexts. (2) The reader must know the most important direct techniques used in clinical treatment of voice disorders. (Contains 7 tables and 2 figures.)