The ion exchange behavior of a sodium and a potassium titanosilicate towards Cs + and Sr 2 + was studied. The materials of interest in this study are titanium and silicon structural analogs of the mineral pharmacosiderite. Pharmacosiderite is a non-aluminosilicate molecular sieve with the framework composition [Fe 4 (OH) 4 (AsO 4 ) 3 ] - .5H 2 O. For the titanosilicate analogs, the framework arrangement of silicate tetrahedra and titanium octahedra create three-dimensional structures with water molecules and charge-neutralizing cations located in the face-centers. Distribution coefficient (K d ) measurements showed that the potassium titanosilicate removed at least 97% of the Sr 2 + from a groundwater simulant that also contained ppm levels of Ca 2 + , Mg 2 + , K + , Cs + and Na + . Similarly, the sodium phase removed about 98% Cs + from the groundwater solution. These preliminary K d values provide an indication that these exchangers may act as potential Cs + and Sr 2 + sorbers for groundwater remediation applications. The sodium and potassium phases were also tested as potential exchangers for Cs + and Sr 2 + in different nuclear waste simulants. While the sodium phase showed little to no preference for Cs + in highly acidic or basic solutions containing large concentrations of NaNO 3 , the potassium phase yielded a Sr 2 + K d of around 7100 ml g - 1 in 2.5 M NaNO 3 /1 M NaOH solutions, and a K d of 3500 ml g - 1 for a solution containing 5 M NaNO 3 /1 M NaOH.