The aim of the present work is to develop a simple and low cost pneumatic metering device to be suitable for planting some medicinal and aromatic seeds (dill and coriander). To fulfill this objective, a developed planter with the pneumatic precision metering device was fabricated and tested in both laboratory and field. The performance of the developed planter was studied under some different operating conditions and compared to the traditional method. Physical and mechanical properties of seeds were investigated to optimize the design of the planters components. The experimental results in laboratory revealed the following: The feeding rate and the application rate of dill and coriander seeds increased with increasing the metering device rotational speed, increasing vacuum tube hole numbers and increasing forward speed. The experimental results in the field revealed the following: The field capacity recorded (0.20 and 0.016 fad./hr.) and (0.29 and 0.025 fad./ hr.) for dill and coriander crops with the developed machine and manual planting respectively. While field efficiency recorded (95.25 and 95.35%) for dill and coriander crops with the developed planter. At longitudinal direction; the maximum values of coefficient of variation recorded (34.67 and 27.73%) for dill and coriander crops with manual planting, while the minimum values recorded (11.75 and 5.97%) for dill and coriander crops with the developed planter. The highest values of seed yield recorded (0.317 and 0.975 Mg/fad.) with the developed planter and manual planting for dill and coriander crops, respectively. The minimum values of consumed energy were (14.21 and 19.99 kW.hr./fad.) for coriander crop with manual planting and the developed planter. While the maximum values were (22.2 and 28.98 kW.hr./fad.) for dill crop under the same conditions. The lowest cost per unit of production it recorded (24.88 and 73.62 LE/fad.) for dill crop with the developed planter and manual planting, respectively. While with coriander crop it recorded (149.43 and 356.36 LE/fad.) under the same conditions.