The main purpose of this study was to test the validity and reliability of FIPS as an assessment tool for pain in children. The subject were 81 children whose ages ranged from 3 to 14 years old who were experiencing pain from an intramuscular injection. 40 were being seen in a local primary hospital and 41 in a university hospital. The data were collected in two settings at a 6 month interval, the first was on Nov. 5th 1991 in a local clinic by one doctor, the second was on May 1st. 1992 in a university hospital by two nurse. McGrath's(1985) face interval cards and weight box scale which is a numeral scale that contains from one to five boxes of cards were used as measures. To analyze the subject's ability to use the face scale and weight box scale, statistical frequency was employed. To determine the difference in the rated pain intensity on the face interval scale and the weight box, Pearson correlation coefficent and t-test were employed. To compare the difference in the rated pain intensity of the face interval scale and the weight box scale according to subject's general characteristics, X2-test was employed. The findings were as follows; 1. The subject's ages were from 3 to 14 with a mean age of 8.3 years old. There were 54(66.7%) male children and 27(33.3%) female children. 2. The number of subjects who correctly displayed cards ranging from none to severe pain was 66(81. 5%) and the number who correctly compared two cards 3 times was 73 (90.1 %). 3. Correlation coefficents between each level card of the FIPS and WBS(Weight Box Scale) were r= .52~.80 P<0.01. 4. There was no statistical difference in rating of the intensity on the FIPS and WBS.(t=1.12~1.02, P<0.22~ 0.45). 5. The differences in rating pain intensity according to the children's general characteristics were related to age (X2 =8.94, P<0.05), but not to sex (X2=0.23, P=0.80).