The selection of North Sea haddock, saithe and cod is evaluated using the twin trawl technique for: (i) a 120 mm diamond mesh cod-end (standard cod-end); (ii) a 120 mm cod-end fitted with a 110 mm square mesh panel (cod-end+panel); (iii) a 120 mm cod-end with a 35 mm selection grid fitted in the extension (cod-end+grid). For haddock, there was no significant difference in the selection of the standard cod-end and the cod-end+panel. The 50% retention length ( l 50) of these nets increased from ∼31 to ∼38 cm as catch increased from 0.3 to 0.7 t. The l 50 of the cod-end+grid was ∼37 cm and did not depend on catch size. Little can be said about selection for catches above 0.7 t due to lack of data. The selection range of the cod-end+grid was ∼1 cm smaller than that of the standard cod-end and the cod-end+panel. For saithe, there was no evidence of any differences in selection between nets, but l 50’s increased from ∼44 to ∼49 cm as catch increased from 0.3 to 0.7 t. There was no evidence that either net type or catch size influenced the selection of cod. The l 50 of cod was ∼45 cm. The saithe and cod results should be treated with caution as they are based on limited data.