The successful design of specific RNA binders requires intimate knowledge of RNA structure, folding, and recognition. Investigation of the interactions between aminoglycoside antibiotics (such as kanamycin A and B, R1 = OH and NH2, respectively, R2 = OH) and RNA has unraveled certain recognition rules; we propose a recognition model suggesting three-dimensional electrostatic complementarity and discuss issues of binding specificity and factors that have to be considered in designing new RNA binders.