Defective castings produce unnecessary costs for foundries. Common flaw in spheroidal graphite cast iron castings are shrinkage defects. In literature it is suggested that by controlling the graphite precipitation it is possible to suppress the shrinkage propensity of the melt. The most influential way of effecting the graphite precipitation is inoculation. In this work the effectiveness of different commercial inoculant products and inoculation methods in reducing the shrinkage defects on cast component were researched. Significant difference in performance was observed between ladle and stream inoculation methods in preference of stream inoculation. Differences were also seen between different inoculants and how they behaved in combinations when ladle and stream inoculants were added simultaneously. It was observed that not all of the combinations were beneficial. In order to decrease the cost caused by shrinkage defects a proper selection of inoculation method and inoculant is of importance.