Throughout the present paper, K denotes a complete, non-trivially valued, ultrametric (or non-archimedean) field. Sequences, infinite series and infinite matrices have their entries in K. The sequence spaces m λ , c λ , c λ 0 were introduced in K earlier by the author in [8–10] and some studies were made. The purpose of the present paper is to characterize the matrix classes (c λ 0 , c µ 0), (c λ 0 , m µ), (c λ 0 , c µ) and (c λ , c µ 0).