A series of model tests in waves were conducted to measure the green sea loads that act on deck and hatch covers due to shipping water. A model of bulk carrier was used. The tests were carried out in irregular waves of which significant height is 10.6 meters and peak period is 14 seconds. In order to discuss the effects of wave heading and ship forward speed on the green sea loads, the model tests were made in several combinations of wave heading and ship speed conditions. It was confirmed that the deck wetness and green sea loads will be reduced considerably if the wave heading is altered to the quarter or beam seas or the ship speed is reduced.In order to assess the experimental results quantitatively, green sea loads were estimated by the practical estimation methods that were developed by the one of authors. Having compared with measured results, it was found that the estimated results were in good agreement with measured ones. It is concluded that the experimental results were rational.Comparison of green sea loads between measured results and present rules, ICLL66 and IACS UR-S21, was made. Although it is difficult to directly correlate measured values with the rules, mean values tend to be larger than the ones of ICLL66. It is also found that the green sea loads defined in IACS UR-S21 is ranked to somewhere between 1/10 and 1/3 significant values in relation to the measured results.