The use of ultrasound radia- tion for the extraction of Cr, K, Na, Pb, and Zn in NPK fertilizer samples was investigated, and their determination by flame atomic absorption (FAAS) and emission spectrometry (FAES). Extraction was performed using 0.05 g of sample, 5.0 mL of HNO3+HCl (50% v/v), and six steps of sonication (20 minutes) in an ultrasound bath, followed by homogenization with a vortex mixer (1 minute). The LOD and LOQ values ranged from 0.6 and 1.8 mg kg-1 and from 3.1 to 6.1 mg kg-1, respectively. The method showed adequate preci- sion (RSD < 5%) and accuracy (recoveries between 90 and 103%). The proposed method requires only small amounts of sample and reagents. All sample pretreatment is carried out in one single flask which avoids sample contamination and ana- lyte loss. The analyte concentra- tions in the samples were found to be below the maximum limits as established by Brazilian legisla- tion.