In 2006, following the European Directive 2002/49/CE, the Portuguese government adjusted its legal framework regarding noise, issuing the decree-law no. 146/2006, introducing a new noise indicator (Lden) and period (evening). These two main changes implied the revision of the Portuguese Noise Code and, in January 2007, was approved the third Portuguese Noise Code (decree-law no. 9/2007). These two pieces of legislation defined urban forms of occupancy, such as: Mixed Zone, Sensible Zone, Sensible Receivers, Dense Urban Areas and Quiet Areas within or outside city limits for which noise limits were settled regarding two periods of a day: den (daytime-evening-night) and night. In addition, enforced the importance of territorial planning instruments to prevent noise annoyance (noise maps and noise conflict maps) and the need to reduce noise levels wherever they exceeded the established limits (action plans and municipal noise reduction plans). This paper analyses the development of Portuguese Guidelines for these two noise reduction plans, namely, legal framework, completion deadlines, minimum conflict limits, cost-benefit analysis and the associated administrative and technical procedures. Two case studies, indicative of the Portuguese median cities, are also commented.