Two field trails were conducted at Sakha Agricultural Research Station (Kafre EI-Sheikh) Governorate in two successive seasons, 1995/ 1998 and 1996/1997 to find out the effect of fertilization and harvest‌ing date on growth behavior and chemical constituents of sugar beet plants. Sugar beet variety viz. 'Plan' was sown during the first week of October in both seasons. The present work included 24 treatments representing the com-bination between farmyard manure levels (with and without FYM applica-tion), three mineral nitrogen doses [Without application (control) 45 kg Med. and 90 kg Med.] two application date of phosphorus fertilizer (With land preparation (WLP) or band in rows at sowing (WS) and two harvesting dates (After 180 days from sowing and after 210 days from sowing). The important results could be summarized as follows: • There was a gradual and significant increase in sugar beet root diame- ter with increasing the applied doses of nitrogen up to 90 kg N/fed. - Root diameter was not affected significantly by time of phosphorus ap-plication. However, phosphorus application with land preparation most‌ly produced thicker sugar beet roots than the other application treat‌ment In most cases. - Sugar beet root length positively responded to the organic manure (FYM) application. - The difference between the two application dates of phosphorus was not high enough to reach the level of significance in their effect on root length and root fresh weight/plant. - Top fresh weight/plant significantly responded to the application of or-ganic manure. 45 and /or 90 kg/fed. distinctly improved fresh weight of sugar beet top/plant and values of leaf area index (LAI) respective‌ly. - Application of nitrogen fertilizer attained a pronounced increase in the 'a and b' chlorophyll content of sugar beet leaves as well as caroti‌noids. - Increasing the applied rates of nitrogen negatively affected the total soluble solids (TSS %), however this effect was insignificant on the val-ues of sucrose %.