Pre-flocculated AKD dispersions were used to size laboratory sheets. The cationic AKD dispersion was pre-flocculated in a Britt Dynamic Drainage Jar. Carboxymethylcellulose and white water from a linerboard mill were used as flocculating agents. The particle size distribution was determined to verify the flocculation. Laboratory sheets sized with pre-flocculated AKD dispersions were made in a dynamic sheet former. The sizing efficiency was evaluated with the 60-second Cobb value, contact angle measurements and quantitative analysis of the total AKD content in the laboratory sheets. The results show that sizing with pre-flocculated AKD improved the sizing efficiency significantly, due to an increased retention. This clearly indicates that agglomerates can be used for internal sizing provided that the flocculation process is controlled. (14 refs.)