Antimicrobials are important to treat diseases in aquaculture and the objective of this study was to evaluate the quality of antimicrobial products commonly used in white leg shrimp (Litopenaeus vannamei) aquaculture in Northern Vietnam. A total of 25 antimicrobial products were obtained from 20 chemical shops including 12 products declared to contain a single antimicrobial, nine products with a mixture of two different antimicrobials and four products containing a mixture of three different antimicrobials. Ultra High Performance Liquid Chromatography coupled to Mass Spectrometry was used to analyse the concentration of the declared antimicrobials. Results revealed that only 1/12 products with a single antimicrobial contained an active substance within ± 10% (accepted level of variation) of the concentration declared on the product label. More than half of the products contained antimicrobial concentrations within < 1.0% to 90% of the declared concentration. The majority of the products provided inadequate or incorrect information on specific diseases to be treated, instructions on how to prepare medicated feed, withdrawal time, as well as instructions about personal protection measures. The documented poor quality of antimicrobial products and inadequate labelling has negative impacts on effective disease treatment; contribute to development of antimicrobial resistance, and the use of such products is associated with food safety and occupational health hazards. There is an urgent need to strengthen diagnostic services, legislation and control of antimicrobial products in shrimp aquaculture and educate farmers on prudent antimicrobial use practices.