This study was carried out to clarify effect of parity on reproductive performance and characteristics, and relationship between reproductive traits in swine. Total 320 heads of pregnant two-breed crosses between Landrace and Large Yorksshire or Duroc or Hampshire were used and divided equally into two groups; the lst to 3rd parity and the 4th to 6th parity, and reproductive performance or characteristics of each group was investigated. Also, the relations between reproductive traits were estimated on the basis of data from 320 litters (3,497 pigs farrowed and 2,800 pigs 30-day weaned). The results obtained are as follows: 1. Total length of furrowing and interval of furrowing from pig to pig of the 1st to 3rd parity were 5.26±2.89 hours and 18.98±8.13 minutes, and the length and interval of the 4th to 6th parity were 6.23±2.79 hours and 21.10±10.34 minutes respectively, and the length and interval of the 4th to 6th parity were significantly (5% to 1 % level) longer than that of the 1st to 3rd parity. 2. Average litter size, number of initial suckling pigs and number of survival pigs at a weeks age of the 4th to 6th parity were significantly (P $lt; 0.01) larger than those of the 1st to 3rd parity. 3. Number of weaning pigs per litter of the 1st to 3rd parity was significantly (P $lt; 0.05) smaller than that of the 4th to 6th parity. 4. Survival rates of piglets during lactation of the 1st to 3rd parity and the 4th to 6th parity were 90.78±9.21, and 87.86±12.12%, and the 1st to 3rd parity showed significantly (P $lt;0.05) better survival rate than the 4th to 6th parity. 5. An increase in litter size was significantly (5% to 1% level) correlated with a decrease in birth weight (r = -0.13), survival rate during lactation (r = -0.50) and interval of farrowing from pig to pig (r = -0.12). 6. An increase in number of initial suckling pigs was significantly (P $lt;0.01) correlated with an increase in number of survival pigs at 3 weeks age (r = 0.76), a decrease of weaning pig weight (r = -0.23) and a daily body weight gain during lactation (r = -0.21). 7. Survival rate of piglets during lactation was significantly (5% to 1% level) correlated with birth weight (0.14), number of weaning pigs (0.15) and interval from weaning to conception (0.22).