Cell surface lectins recognize diverse glycans and these interactions are implicated in a wide range of physiological and pathological processes. Accordingly, understanding lectin-mediated recognition events and blocking glycan-protein interactions associated with diseases are of great importance for both basic biological research and biomedical applications. To investigate recognition of glycans by lectins expressed on mammalian and pathogen cell surfaces, we prepared three Lewis antigen conjugated, fluorescent magnetic nanoparticles (FMNPs). Although glycan- conjugated NPs have been widely used to detect cell surface lectins, dual modal (fluorescent and magnetic) glycoNPs have not been employed to study lectin-associated recognition events. In the initial study, when DCEK, DCEK-DC-SIGN and DCEK-SIGN-R1 cells were incubated with glycosylated FMNPs, Lea and Leb but not H1 conjugated NPs were recognized by DC-SIGN and SIGN-R1 expressing mammalian cells, and, subsequently, entered the cells. However, mannan, which is a tight ligand for DC-SIGN and SIGN-R1, suppressed the binding of glycoNPs to the cells. Next, when H. pyroli J99 strain expressing BabA was incubated with glycoNPs, Leb and H1 conjugated but not Lea conjugated NPs bound to this strain. However, these glycoNPs did not interact with H. pyroli strains lacking BabA. We also used glycoNPs to enrich BabA expressing H. pyroli by using a magnet. The present study show that fluorescent magnetic glyconanoparticles can serve as useful tools to sensitively detect lectins expressed on pathogen and mammalian cell surfaces. This study also provide opportunities for developing finely tuned multifunctional nanoparticle-based drug and diagnostic nanoplatforms.